Appendixes to TCRP RRD 84: Audible Signals for Pedestrian Safety in LRT Environments (2007)

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1 Appendix A Synopsis of Prior Research (Literature Review) (Prepared November 2003) INTRODUCTION AND PURPOSE The purpose of this literature review is to summarize the relevant literature and research that has been conducted in the area of audible warnings for pedestrians at light rail transit (LRT) grade crossings. The numerous references outlined in this report provide research findings and recommendations for grade crossing treatments or for pedestrian audible warnings; however, there has been limited research conducted on the effect of audible warning devices on pedestrian behavior at LRT grade crossings. This report provides a summary of the research separated into the following areas: • Pedestrian Treatments at LRT Grade Crossing • Human Factors • Audible Warnings • Considerations for Persons with Disabilities Following the summary of each area is a list of selected references and short summary of each reference that describes the particular aspects of the literature reviewed. It is clear through the literature review that although research has been conducted which evaluates various factors of audible devices at grade crossings, a study has not yet been conducted that clearly identifies the impacts of pedestrian audible devices at LRT grade crossings. Therefore, TCRP Project D-10 will be the first comprehensive review of pedestrian audible devices at LRT grade crossings which conducts research of the effects of innovative devices on pedestrian behavior. PEDESTRIAN TREATMENTS AT LRT GRADE CROSSING Much attention has traditionally been given to safety issues associated with motor vehicle/light rail vehicle (LRV) crossings. There has been somewhat less attention given, however, to issues associated with pedestrian/light rail vehicle conflicts, including collisions, near misses, evasive actions, and illegal pedestrian movements. While there are generally fewer pedestrian/light rail vehicle collisions, the results of such collisions are often severe given the inherent vulnerability of the pedestrian. Compounding this problem, new generations of light rail vehicles are quieter than previous designs. As such, pedestrians are not as aware of oncoming light rail vehicles, potentially increasing conflicts. The most comprehensive literature to date that provides a review of grade crossing treatments at LRT grade crossings can be found in TCRP Report 17: Integration of Light Rail Transit into City Streets (Korve et al, 1996) and TCRP Report 69: Light Rail Service – Pedestrian and Vehicular Safety (Korve et al, 2001). These two reports identify effective traffic control devices, public education devices and enforcement techniques for LRT grade crossings. The information in the two reports is based on interviews with 14 LRT systems throughout North America, additional data collection and field testing of grade crossing treatments. TCRP Report 69 reports that at LRT grade crossings where the LRV operates at speeds up to 55 km/h (35mph), 18% of pedestrian collisions result in fatalities. Where the LRV operates at speeds in excess of 55 km/h (35 mph), 29% of pedestrian collisions result in fatalities. In addition, many of the injuries obtained by pedestrians are life altering, including dismemberment and long term trauma.

2 With respect to pedestrian audible devices at LRT grade crossings, TCRP Report 69 describes that at higher speed LRT crossings controlled by flashing light signals and automatic gates, some LRT agencies turn off the bell once the automatic gates have descended. Cessation of the wayside crossing bells is sometimes necessary in residential neighborhoods where excessive noise is usually a concern. The report recommends that some form of audible wayside warning should be provided for the visually impaired. As an alternative to crossing bells, small audio devices (similar to a back-up alarm on a truck, such as those found on portions of the Sacramento LRT system) could be installed in the crossing hardware to warn pedestrians of an approaching LRV. These small audio devices could be softer than a clanging bell and also focused on the sidewalk itself. In addition to grade wayside devices such as those described above, LRVs are equipped with bells, whistles and/or horns. TCRP Report 69 describes that usage of LRV bells, whistles, and horns at LRT crossings varies widely based on local practices, ranging from “silent” crossings during the evening hours where the LRV operator only sounds the horn if there is imminent danger to crossings where the LRV operator sounds the horn in the long blast-long blast-short blast-long blast” pattern all hours of the day (every time the LRV passes through the crossing). The use of the bells or horns is based on the operating procedure of the transit agency and may be based on considerations such as the speed of the LRV through the crossing as well as community impacts. Some agencies require the train operator to sound the horn at all crossings, while other agencies request that the operator to only sound the (quieter) bell through crossings and sound the horn at their discretion if there is an imminent hazard. Another research study which focused on the use of audible devices at LRT grade crossings is entitled Effects of Pedestrian Treatments on Risky Pedestrian Behavior (Siques, 2002). This paper discusses a research study conducted at the Portland, Oregon LRT System (Tri-Met) which evaluated the effects of various pedestrian treatments on risky behavior. The report describes that the Portland LRT System has installed pedestrian audible devices at various locations in a demonstration project to determine the effect of the audible device on risky pedestrian behavior. The audible device announces the message “Train Approaching, Look Both Ways” in both Spanish and English when a train activates the crossing control devices. The results of the device were mixed based on the type of behavior observed. Pedestrian Warning and Control Devices, Guidelines and Case Studies (Siques, 2001) also provides recommendations on how to identify potentially hazardous crossings and appropriate treatments. The paper identifies four basic factors that govern the level of pedestrian safety at crossings. These factors are: • pedestrian awareness of the crossing, • pedestrian path across the trackway • pedestrian awareness of the approaching LRV • pedestrian understanding of the potential hazards at grade crossing Each factor is discussed and case studies are presented where innovative treatments have been used to increase pedestrian safety at LRT grade crossings. The use of audible devices, either wayside or on train, is also related to the alignment type of the LRT crossing. Alignments where the LRV travels in a separate right-of-way or is gated have different operating procedures than alignments where the LRV is operating in mixed flow or on-street environments controlled by traffic signals. Audible devices at traffic signaled controlled intersections are discussed further in the Human Factors and Considerations for Persons with Disabilities sections of this literature review. The following summary of selected studies provides background on additional studies conducted on pedestrian warning devices at grade crossings: APTA Rail Safety Committee—Grade Crossing and Pedestrian Safety Task Force. LRT Grade Crossing Design Features. June 12, 1994.

3 This report provides a synopsis of the various approaches to grade crossing design taken by LRT systems in the U.S. and Canada. It represents one component of the ultimate objective of the task force, which is “to investigate and report on the state of the art of grade crossings and pedestrian safety and to develop recommendations. The information presented includes detailed descriptions of the grade crossing design features of several of the North American light rail systems. Coifman, B. and Hansen, M. IVHS Warning Systems for Light Rail Grade Crossings. Institute of Transportation Studies, University of California at Berkeley. 1994. This report quantifies the costs of light rail grade crossing accidents with left-turning vehicles and identifies the causal events leading up to a collision and the factors that may contribute to the probability of injury. A classification of costs is developed to motivate the discussion of collision countermeasures. It is noted that compared to automobile accidents, pedestrian and bicycle accidents tend to have significantly higher claims and legal costs. The report concludes with a discussion of technologies for an intelligent system to respond to hazard conditions. The specific technologies discussed are classified according to the tasks they accomplish — automobile detection, hazard prediction, and graduated response based on predicted hazard level. Federal Highway Administration, U.S. Department of Transportation. Manual on Uniform Traffic Control Devices for Streets and Highways. Millennium Edition. Washington, DC (2000). This manual sets forth the basic principles that govern the design and usage of traffic control devices for different classes of road and street systems. These devices include "signs, signals, markings, and devices placed on, over or adjacent to a street or highway by authority of a public body or official having jurisdiction to regulate, warn, or guide traffic." Chapter 8 of this manual sets forth guidelines for traffic control systems for railroad-highway grade crossings. Chapter 10 of this manual presents standards and guidelines for the design, installation, and operation of traffic control devices, such as signs, markings, and automatic gates, at grade crossings of highways and light rail transit. Many of the guidelines presented are different from those prescribed for crossings of railroads and highways because the operating characteristics of LRVs are different from conventional trains. The situations when such devices should be installed and precise specifications for installation are described in great detail. Pedestrian grade crossings are given special attention, with a description of specific pedestrian treatments. Institute of Transportation Studies. "Special Report: Pedestrian Safety." Tech Transfer, No. 45. Washington, DC (April 1994), pp. 2-7. This report contains several articles describing the California pedestrian safety plan, sources of local funding for pedestrian safety programs, and two pedestrian enhancement projects. An annotated bibliography of recent publications addressing pedestrian safety issues is also included with this report. The report identifies some of the pedestrian safety concerns of local and state agencies. Stokes, R. W., Rys, M. J., and Russell, E. R. “Motorist Understanding of Selected Warning Signs,” ITE Journal. Washington, DC, (August 1996) pp. 36 - 41. This report documents the results of a survey taken in the state of Kansas to test driver understanding of common warning signs. In this study, driver understanding was tested using a multiple choice test administered at selected survey stations in several counties within Kansas that were deemed to have similar demographics as the state of Kansas as a whole. Open-ended surveys were also administered as part of this research. As the survey results reveal, the use of

4 multiple choice surveys introduces bias by limiting the choice set of possible interpretations of the warning signs. With the multiple choice surveys, test subjects had a better chance of identifying the correct response from the options listed. The use of open-ended questions helped to compensate for this bias. One shortcoming of this survey methodology that the authors acknowledge is that the surveys focused on assessing on whether or not the driver understood the exact meaning of the traffic warning signs, rather than assessing if the driver’s understanding of the sign would generate an appropriate behavioral response. Transportation Research Board, National Research Council. TCRP Report 17: Integration of Light Rail Transit into City Streets. National Academy Press, Washington, DC. 1996. This report presents the safety and operating experiences of ten North American light rail transit systems operating in shared (on-street or mall) rights-of-way at speeds that do not exceed 35 miles per hour. Although LRT systems are safer than the motor vehicle-highway system, accidents remain a problem due to motorist and pedestrian inattention, disobedience of traffic laws, and confusion about the meaning of traffic control devices. Research found that traffic control treatments for safety and efficient operations at LRT grade crossings vary from system to system and even between different locations in the same system. This report proposes several guidelines to be adopted by the National Committee on Uniform Traffic Control Devices for signs and traffic control systems for uniform application at light rail-highway grade crossings. Transportation Research Board, National Research Council. TCRP Report 69: Light Rail Service – Pedestrian and Vehicular Safety. National Academy Press, Washington, DC. 2001. This report identifies, validates and recommends safety enhancements to reduce incidents at higher speed LRT grade crossings, including a study on the effectiveness of pre-signals. Pedestrian treatments at LRT grade crossings are discussed in detail and a Pedestrian Controls Decision Tree is presented that describes what types of pedestrian treatments should be used at LRT grade crossings. The use of pedestrian treatments are based on various warrants, including sight distance, school zones, LRT speed and the level of pedestrian activity. HUMAN FACTORS Typical warning systems currently used to alert pedestrians to potential threats include horns or bells operated at the grade crossing. Some of these devices are sounded until the gates are down while others are sounded until the train has passed. These warnings are typically quite loud and can generate significant community opposition. Pedestrians often engage in risky behaviors at crossings (Siques, 2002), and it is not likely that their failure to respond to audible warnings is a result of them not being sufficiently loud. However, they may not be sufficiently salient or informative. The present use of audible warnings is based on limited research and historical practice. At this juncture the research community is faced with the choice of improving the old system of warnings designed and implemented at a time when best guesses predominated over carefully controlled research studies or to design a more effective warning system based on current knowledge of factors influencing human behavior and utilizing modern technology. Selecting the later strategy will not only produce a more effective system but will also better meet the needs of persons with disabilities. Novel approaches that should be evaluated include: 1. The effectiveness of auditory icons such as the sound of the train emanating from the direction the train is approaching from, with or without the sound of the train’s horn (such directional cues have been shown to reduce the time and effort to identify a potential threat in other

5 applications); 2. The addition of voice messages along with auditory icons, which could provide a specific warning of the occurrence of a second train coming; and 3. The integration of auditory icons with visual icons, in order to provide redundant information in two sensory channels. An integrative approach that includes all three components should produce the best level of pedestrian compliance as well as best meet the needs of the visually and hearing impaired communities. The adoption of this approach could also lead to the use of lower sound levels if good human factors practices are followed. The remainder of this review focuses on research that bears upon adopting this approach. Pedestrians in urban areas move through a richly textured visual environment. As intelligent transportation system (ITS) displays are introduced, they need to compete with other stimuli in this complex environment. Auditory messages can supplement some of these displays. System engineers often fail to take into account the behavioral principals that influence the behavior of pedestrians when designing auditory warning systems, reducing their efficacy. Many of these systems rely on audible warnings operated at excessive volume, which provide limited information in a non-intuitive manner. These warnings can create a startle response and lead to confusion if they are poorly designed. A more reasonable approach involves the use of auditory icons rather than arbitrary symbols. An auditory icon is a noise normally associated with the object that someone is being warned about such as the sound of breaking glass, or screeching brakes (Mynatt, 1994). In a light rail environment icons could consist of the noise associated with an approaching train and its horn or whistle delivered via a wayside speaker. One would expect that the reaction to auditory icons to be more intuitive than the response to arbitrary warning stimuli, and available evidence indicate that auditory icons are more effective warning stimuli than arbitrary symbolic sounds (Belz, Robinson, & Casali, 1999). Auditory icons can also be presented in a directional manner, which facilitates orientation in the direction of a potential threat. Wayside horns are one way to deliver an auditory icon and the noise of an approaching train presented along with the train whistle or horn might be the most intuitive warning icon. Verbal warnings presented in one or more languages could also be used to support audible warnings. One advantage of audible warnings is that they can convey a more specific message than a simple auditory warning or even an auditory icon. One disadvantage is determining how many languages the verbal warning should be presented in for multi-cultural communities. The behavior modification literature has consistently shown that specific prompts or reminders produce better compliance than general prompts or warnings such as a simple auditory alarm. One study examined the use of verbal prompts delivered when pedestrians pressed the push button at a crosswalk controlled by traffic signals (Van Houten, Malenfant, Van Houten & Retting, 1998). When the pedestrian pushed the button the dynamically controlled speakers immediately delivered the verbal message “PLEASE WAIT FOR WALK SIGNAL” and at the start of the WALK indication the message “PLEASE WATCH FOR TURNING VEHICLES WHEN CROSSING _______ STREET” was presented. The percentage of pedestrians not looking for turning vehicles decreased from 16% to 4% and the percentage of pedestrian/motor vehicle conflicts decreased from 2% to 0.5% after the voice warning was introduced. One problem, which needs to be addressed by any light rail auditory, warning system, is the risk of being struck by a second train. A voice message could indicate whether trains are approaching from both directions, or when two trains are approaching from the same direction (e.g., “WARNING TRAINS APPROACHING FROM BOTH DIRECTIONS” vs. “WARNING TWO TRAINS ARE APPROACHING FROM THE EAST”. Research on the intelligibility of speech in a 3-D environment suggests that voice messages originating from the side of the listener produce the best comprehension (MacDonald, Balakrishnan, Orosz, & Karplus, 2002). This finding is interesting given that many warning devices are typically presented from a location ahead of the pedestrian rather than their side. Not only do warnings originating ahead of the pedestrian not optimize interpretation but they also provide no information on the direction that the train is approaching. A sound originating from the side of the pedestrian along the track at a level grade crossing would facilitate the pedestrian using the sound icon to discriminate the direction of the threat. The addition of a supplemental voice message when a second train is approaching should also be most

6 easily interpreted when the pedestrian can hear trains approaching from both directions. The train or whistle sounds can also convey second train coming information by presenting them from both directions with a difference in the sound (difference in the doppler effect for the train whistle could confirm the perception that both trains are both approaching the crossing). This approach could also be used at station locations. The Beltz, Robinson and Casali (1999) study on auditory icons also found better performance when visual icons indicating the direction of the threat were presented along with auditory icons. Van Houten and Malenfant (1999) reported the results of a study at passive rail crossing controlled by a stop sign. The speed distribution of drivers showed a marked decline when an icon showing animated LED eyes that looked both ways was activated when vehicles approached the crossing. In an other study Van Houten and Malenfant (2001) found that a visual display that showed drivers the direction that a pedestrian was crossing, as well as whether pedestrians were crossing from both directions was more effective than a non directional, non iconic flashing warning beacon (analogous to a simple auditory warning device). Both devices were operated by pedestrian detection. The electronic warning sign used in this study could be adapted to warn pedestrians of an approaching train at a level grade crossing by showing an icon of a train approaching from the pedestrians left or right. This device also has the advantage of allowing one to present both icons together when trains are approaching from both directions. One would suspect that integration of a directional electronic sign and a directional auditory display would generate the best pedestrian performance at level grade crossings and station locations. A study is currently underway to evaluate a second train coming warning sign on the Los Angeles County Metropolitan Transportation Authority's (LACMTA's) Metro Blue Line (Khawani, 2001). The following summary of selected studies provides background on additional studies conducted on human response to warning devices: Belz, S.M., Robinson, G.S. & Casali, J.G. (1999). A new class of auditory warning signals for complex systems: auditory icons. Human Factors, 41, 608-618. This simulator based study compared conventional auditory warnings (tonal sounds) with auditory icons (sounds that represented a particular threat) with or without a visual iconic display, which indicated the type of threat. Measures included brake response time and accident occurrence. Participants were commercial drivers. The auditory icon selected for front-to-rear crash avoidance was the sound of screeching brakes, and the auditory icon for side collision avoidance was a long horn honk. Response time with auditory icons was markedly less than with the traditional auditory warning stimuli. It is interesting to note that no significant difference was found between the traditional auditory warning and the no-display condition. Participants also had markedly fewer side collisions with the auditory icon than the traditional auditory warning. Khawani, V. (2001). "SECOND TRAIN COMING" warning sign demonstration project. Transportation Research Record, 1762, 32-36. This paper describes a project currently underway to evaluate an ITS sign to warn pedestrians of the hazard of a second train arriving. This scenario has resulted in 14 pedestrian crashes and 4 fatalities at the LACMTA’s Vernon Avenue HRI since the start of operation in 1990. This study describes the outreach and awareness program associated with the sign and the method being used to evaluate its effectiveness. Results of the effectiveness of the sign were not presented in the report, as the study was ongoing when the report was published. MacDonald, J.A., Balakrishnan, J.D., Orosz, M.D. & Karplus, W.J. (2002). Intelligibility of speech in a virtual 3-D environment. Human Factors, 44, 272-286. Researchers used a simulated air traffic control environment to evaluate the effects of special configuration on the detection of auditory speech warnings in an environment with multiple sound

7 feeds. The simultaneous presentation of multiple sounds in an environment increases the difficulty of interpreting and responding to speech messages. This research was conducted in both a virtual 3-D environment and a free field (real space) environment. The results indicated that the left/right axis is the critical factor to consider in auditory display design. Speech was interpreted best when presented from the side rather than presented ahead. These findings are interesting because the most “natural” position for a sound source (in front of the speaker) was the least effective for “intelligibility”. The TCRP Project D-10 team suspects that looking at the source is considered most natural because it allows detection of non-verbal social cues from speakers and because of the importance of vision has an early warning detection system. Van Houten, R. & Malenfant, J.E.L. (2001). ITS Animated LED Signals Alert Drivers to Pedestrian Threats, ITE Journal, 71, p. 42-47. An iconic electronic sign was evaluated which indicated to drivers approaching a indoor parking garage exit or a multilane crosswalk, the presence and direction of a pedestrian crossing in front of them. In the first location the view of the pedestrian was visually screened by the walls of the parking garage and in the second location the view of the pedestrian could be visually screened by a vehicle that yielded in another lane. When a pedestrian was crossing from the driver’s right, an LED pedestrian symbol walking from the right was illuminated on the right of the sign and animated LED eyes located in the center of the display looked repeatedly to the right. When the pedestrian was crossing from the left the LED pedestrian display an LED pedestrian symbol walking from the left was illuminated on the left of the sign and the animated eyes looked to the left. When pedestrians approached from both directions, both pedestrian symbols were illuminated and the eyes looked back and forth. This sign increased the percentage of drivers looking for the pedestrian, increased driver yielding to the pedestrian, and produced a marked decrease in the incidence of pedestrian/motor vehicle conflicts that involved either the pedestrian or driver taking evasive action. A flashing yellow beacon that was illuminated when pedestrians were present produced much smaller effects than the iconic sign. The TCRP D-10 team believes that this sign could easily be adapted to warn pedestrians of approaching trains indicating the direction that train is approaching from. It can also indicate when trains are approaching from both directions. Van Houten, R., Malenfant, L. Van Houten, J., & Retting, R.A. (1998). Auditory Pedestrian Signals Increase Pedestrian Observing Behavior and Reduce Conflicts at a Signalized Intersection. Transportation Research Record, No. 1578, 20-22. A voice message was used to remind pedestrians to watch for turning vehicles when crossing with the WALK signal. The voice message increased pedestrian observing behavior and reduced pedestrian motor vehicle conflicts after it was introduced. Behavior improved the longer the system was in effect showing that the results were not a novelty effect. Such a system could also be useful to visually impaired pedestrians. AUDIBLE WARNINGS Audible warnings at protected grade crossings typically consist of some combination of train horns, train bells, and crossing gate bells. There has also been some recent effort to reduce community noise impacts by using wayside audible warnings in place of the train horns. These are commonly referred to as “wayside horns.”

8 Almost all of the published research on audible warnings at rail grade crossings is based on mainline rail systems, either freight, passenger or commuter rail. Over the past 10 to 15 years there has been a considerable amount of research sponsored by the FRA on the safety benefits and the corresponding noise impacts of sounding train horns before rail-highway grade crossings. The conclusion of this research is that, at least for mainline rail, sounding the train horns prior to grade crossings significantly reduces the potential for motor vehicle/train accidents. This information is particularly relevant for grade crossings with whistle bans. Most of this research has not considered pedestrian safety and has only focused on motor vehicle related incidents. Although the FRA research demonstrates the safety benefits from sounding train horns prior to highway-rail grade crossings on mainline rail systems, it is not clear whether and how this research applies to light rail pedestrian crossings. Because there is substantial evidence indicating that the routine sounding of train horns in advance of grade crossings has the potential to reduce motor vehicle/train accidents at grade crossings, it is reasonable to expect that the train horns also reduce the potential for pedestrian incidents. One question is how applicable the research on mainline rail systems is to light rail systems. Some of the important differences between the audible warnings used on mainline rail and those used on light rail systems are: ƒ Train Horn Sound Levels. 49 CFR, Chapter 11, part 222.129(a) requires that train locomotives be equipped with horns that generate a minimum sound level of 96 dBA at 100 feet. In practice, many locomotive horns measure 100 dBA. Although there are no federal standards on the loudness of LRT audible warning devices, state and local regulations, as well as standard industry practice, are typically much lower. For example, light rail vehicles in California are required to have two audible warning devices: one measuring at least 75 dBA at 100 feet and the other at least 85 dBA at 100 feet. ƒ Duration of Horn Sounding. Freight and passenger trains are commonly required to start the horn sequence 1/4 mile from grade crossings and complete the sequence as the lead locomotive passes through the crossing. It is traditional for freight trains to use a long-long-short-long horn sequence as they approach grade crossings. Experience is that there is significant variation in how locomotive engineers perform the sequence. The requirement for sounding LRT horns before grade crossings varies widely. On systems where horn sounding is standard practice, they are usually sounded starting 500 to 1,000 feet before the grade crossing. ƒ Type of Horn. Mainline freight and passenger locomotives are equipped with air-horns that include 3 to 5 chimes whereas light rail vehicles commonly have either electric horns or air horns with only one chime. The electric horns can be programmed with any sound; many are programmed to sound like a freight train horn so the sound will be instantly recognized as a warning of an approaching train. ƒ Horn Position. Locomotive horns are usually mounted on the top of the cab and therefore tend to propagate in a 360° plane. In place of a horn, some commuter rail systems use a whistle mounted on the front of the lead locomotive that is located about 3 feet above the ground. Many horns on light rail vehicles are mounted under the front of the vehicle 2 to 3 feet above the ground. Horns mounted on top of the cab cause the most community noise impact. Locating the horn on the front or under the front of the vehicle tends to focus the warning sound towards the crossing broadcasting less of the sound into adjacent communities. Much of the published literature on audible warning at grade crossings related to the proposed FRA rule on use of locomotive horns at grade crossings (FRA 1995 -2000). As discussed above, this research has shown a clear correlation between routine sounding of train horns prior to grade crossings and the accident rate. This research has all focused on motor vehicle safety. The proposed rule provides guidelines for establishing “quiet zones” where sounding the train horns prior to grade crossings is not

9 required. The primary requirement is that supplementary safety measures be taken that will substitute for the train horn. The supplementary safety measures include four quadrant gates and photo enforcement. Wayside horns are another alternative that is being used in place of sounding train horns. The use of wayside horns has been evaluated for both freight rail and light rail systems. Wayside horns consist of an audible warning that simulates a train horn and is supplemental to the bells and flashing lights at gate- protected crossings. The use of wayside horns has been investigated at a number of highway-rail crossings. Although the focus has been on motorist safety and community noise impacts, there are applications of this technology to pedestrian LRT environments, as well as for communities along LRT lines. Because the wayside horn sound is focused at the grade crossing, the area affected by the warning noise is greatly reduced. One study indicates that, by using the wayside horns, the total land area inside the 70 dBA and 90 dBA maximum sound level contours was reduced by 86% and 98%, respectively. Preliminary feedback from adjacent communities is that they strongly support the use of wayside horns and perceive the wayside horns as a noticeable improvement. Wayside horn systems are now commercially available and have been installed at a number of mainline rail grade crossings. Although the wayside horn concept was evaluated for an LRT system in Los Angeles (Saurenman, 1995), we are not aware of any such systems being installed on North American LRT systems. It is clear that wayside horns can substantially reduce community noise impact, particularly on freight and commuter rail systems where horn maximum sound levels often exceed 100 dBA at residences. Questions still exist on the applicability of wayside horns in an LRT environment where horn sound levels are 10 to 20 dBA lower than on freight rail systems and whether wayside horns can maintain adequate levels of pedestrian safety. Although wayside horns have been found to greatly reduce community annoyance, questions regarding motorist safety have not been fully answered. This is in part due to the difficulty of separating out the numerous factors that affect motorist behavior. For instance, at highway-railroad crossing, motorists are influenced by the crossing arms, flashers, bells, other motorist behavior, and past experiences. Also, motorists are accustomed to hearing the train horn come from either up or down the tracks. Potentially important acoustic cues related to the direction of train are eliminated with existing wayside horn systems. However, some long-term studies suggest that wayside horns provide an effective alternative to train horns. Crossing bells are the other audible warning signal at most highway-rail and pedestrian-rail grade crossings. Protected highway-rail grade crossings on light rail systems are almost always equipped with some combination of gates, bells and flashing lights, often with all three. For protected pedestrian-only crossings, it is common to have bells and lights, sometimes with gates that pedestrians must pull open to cross the tracks. In spite of crossing bells being very common, the AREMA Communications and Signals Manual seems to be the only document with recommended noise limits for crossing bells.1 The sound levels in the standard are: ƒ Section 3.2.60 Recommended Design Criteria for Highway-Rail Grade Crossing Electromechanical Bell (Revised 2000): The recommended specification is: “In the 180° plane occupied by the gong the peak sound reading in decibels (A scale) measured in an Anechoic test chamber at a point 10 ft. from the face of the gong and in increments of 20° should not be more than 105 dBA and not less than 85 dBA.” Under “alternate recommendations” sound levels of not more than 85 dBA and not less than 75 dBA are given. ƒ Section 3.2.61 Recommended Design Criteria for an Electronic Highway-Rail Grade Crossing Bell (Reaffirmed 2000): The recommended specification is: “In a 360° plane the peak sound reading in 1 American Railway Engineering and Maintenance of Way Association, Communications and Signals Manual or Recommended Practices.

10 decibels (A scale) measured in an Anechoic test chamber at a point 10 ft. from the face of the sound horn and in increments of 20° should not be more than 105 dBA and not less than 75 dBA.” The following summary of selected studies provides background on additional studies conducted on audible warning devices: 49 CFR Parts 222 and 229, Use of Locomotive Horns at Highway-Rail Grade Crossings; Proposed Rule, Federal Register, January 13, 2000. This proposed rule on use of locomotive horns at highway-rail grade crossings is applicable to all grade crossings that are part of the national rail system. This means that it is applicable to freight, passenger and most commuter rail systems, but it is not applicable to LRT systems. The FRA is still in the process of preparing a final rule. Perhaps the most controversial aspect of the proposed rule is that existing grade crossing whistle bans would be eliminated unless supplementary safety measures are implemented. Adopting the rule would require upgrading safety measures at numerous grade crossings where whistle bans are currently in place through local ordinances or other agreements. As part of developing the proposed rule, the statistics of train and motor vehicle accidents were evaluated to determine whether, and how much, use of train horns affected the accident rate at grade crossings. The conclusion was that whistle bans result in an elevated accident rate. The proposed rule would result in uniform requirements for sounding train horns at grade crossings. It also provides specific guidance for state and local groups on supplementary safety procedures that are required before the FRA will consider an application for a quiet zone where train engineers are not required to sound the horns. Based on a presentation made by the FRA at the National Grade Crossing Safety Conference in San Antonio, Texas, on November 5, 2003, the Interim Rule will be released by the FRA by the end of 2003 for a 60-day comment period. The Final Rule will be released in the summer of 2004. The rule will also address the use of wayside audible horns. Technical Supplement to the Draft Environmental Impact Statement of the Proposed Rule for the Use of Locomotive Train Horns at Highway-Rail Grade Crossings. FRA, U.S. Department of Transportation, December 1999. This report is a supplement to 49 CFR Parts 222 and 229. The primary goal of the study was to estimate the number of people who would be adversely affected by the noise exposure increases that would result from a nationwide elimination of all current whistle bans. A generalized model of grade crossing horn noise was developed to allow estimating the population that would be affected by eliminating whistle bans. This study is specific to the freight rail system and only has peripheral application to light rail systems. Florida’s Train Whistle Ban, 2nd Edition. September 1992. and Nationwide Study of Train Whistle Bans. FRA, Office of Safety, U.S. Department of Transportation, April 1995. In response to Congressional inquiries, FRA investigated the number of accidents at crossings with nighttime whistle-bans. FRA found that the accident rate for the Florida East Coast Railway Company at 511 grade crossings nearly tripled after the nighttime whistle-bans were imposed. This increase is statistically greater than the increased accident rate at 89 comparable crossings where the whistle-ban had not been imposed. After the whistle ban was eliminated, the accident rate returned to the pre-ban rates. Updated Analysis of Whistle Bans. FRA Office of Safety, U.S. Department of Transportation, January 2000.

11 This study and the update in 2000 represents a careful evaluation of the comparative accident rates at crossings with and without whistle bans. The conclusion of the 2000 update is that “…an average of 63% more collisions occurred at whistle ban crossings with gates than at similar crossings across the nation without bans.” The analysis excluded all events where pedestrians were struck. Safety of Highway-Railroad Grade Crossings, Railroad Horn Systems Research, Volume II, DOT/FRA/PRD-DPOT-VNTSC-FRA, Final Report. Research and Special Programs Administration, John A. Volpe National Transportation Systems Center, U.S. Department of Transportation, 1993. As part of on-going research into the effectiveness of various methods of reducing the number of accidents at highway-railroad grade crossings, the Volpe Center evaluated the use of locomotive horns for warning motorists and their impact on local communities. Acoustic data was used to compute the community noise exposure in the vicinity of grade crossings, which was compared against “normally acceptable” sound levels. The insertion loss and baseline interior noise levels of motor vehicles were obtained to evaluate the detectability of train horns. The interior noise level of the vehicle with the air-conditioning ventilation turned on and with the radio turned on had impacts on the audibility of the exterior noise. Gent, S., Logan, S., and Evans, D. Evaluation of an Automated Horn Warning System at Three Highway-Railroad Grade Crossings in Ames, Iowa. Mid-Continent Transportation Symposium Proceedings, 2000. This research investigated the effects of automated horn warning systems (wayside horns) on community annoyance and overall motorist safety. It was determined that the wayside horn dramatically decreased the land area affected by horn noise and was perceived as a significant improvement by a majority of nearby residents. Although the overall safety provided by the wayside horn could not be accurately determined, the study found no evidence that they are less safe than typical locomotive train horns. Saurenman, H., Roberts, W. Testing of Wayside Horn Concepts for Audio Warnings at Grade Crossings. Harris Miller Miller & Hanson, Inc., September 1995. This report summarized a feasibility study of using a wayside horn system in place of train horns at a grade crossing on the Los Angeles County MTA Blue Line, a light rail line connecting Los Angeles and Long Beach. Because the LRT tracks share right of way with freight rail tracks, the horns on the Blue Line vehicles were set to the FRA standard of 96 dBA at 100 ft in front of the train, which is about 10 dBA louder than the horns on most Californian light rail systems. The wayside horn concept was investigated as a method to achieve the same public safety with less noise impact to residences adjacent to grade crossings. A focus group from the surrounding community was used to evaluate both the warning effectiveness and annoyance potential of the wayside horns. The testing indicated that wayside horns are a valid concept that could provide equal or greater public safety as train horns while reducing community noise levels. The results are equally applicable to pedestrians and motorists. Wayside Horn Sound Radiation and Motorist Audibility Evaluation. Association of American Railroads, May 2000. This study tested a commercially-available wayside horn system in terms of community noise levels and motorist warning. Roop, S. A Safety Evaluation of the RCL Automated Horn System, Texas Transportation Institute, Rail Research Center, May 2000.

12 This study looked at the change in Type 1 and Type 2 violations before and after the installation of a wayside horn system in Gering, Nebraska. The report concluded that, after five years in operation, the wayside horn at this location is an effective alternative to the more intrusive locomotive horn. Horn Investigation Report, Southern California Regional Rail Authority, prepare by LTK Engineering Services, November 1993. This memorandum summarizes noise measurements performed on the horns and whistles installed on Metrolink trains in Los Angeles. Approximately 10 years ago, Metrolink locomotives and cab cars were all equipped with chime air whistles in an effort to reduce community complaints about noise near grade crossings. The whistles were mounted on the front of the locomotives and cab cars approximately 3 feet above the ground. In contrast, the horns were located on top of the vehicles about 15 feet above the ground. The horns and whistles were adjusted to meet the FRA regulations directly in front of the train. In a perpendicular direction, the data show the whistles are 10 to 20 dBA quieter than the roof mounted horns. State Regulatory Requirements Governing Warning Signals for Light Rail Vehicles The requirements for audible warning signals of light rail vehicles operated by state-chartered transit authorities are regulated principally by state agency and/or transit authority policy. These requirements are customarily based on a codification of experience and common practice, rather than on systematic research or quantitative analysis. For example, a single paragraph (§3.04) of California Public Utility Commission General Order 143-B establishes that every light rail vehicle operated by one of the state’s transit authorities “shall be equipped with a bell or horn capable of producing a clearly audible warning measuring at least 75 dBA at a distance of 100 feet from the vehicle. In addition, every LRV operating on a separate right-of-way over motor vehicle grade crossings shall be equipped with a horn or whistle measuring at least 85 dBA at a distance of 100 feet from the LRV.”2 The criteria for warning effectiveness that these requirements are expected to satisfy are not explicit. It is thus unclear what minimal warning time such signals are expected to provide to pedestrians or motorists at various light rail running speeds; whether the warning signals are expected to be as effective at crossings in noisy urban or industrial ambient noise environments as they are at quieter suburban crossings; whether the warning signals are intended to protect people with some degree of hearing impairment; what rate of complaints about warning signals from residents of neighborhoods near light rail rights-of-ways are considered tolerable; and so forth. Further, the requirement for the lower level warning signal implies that “a bell or horn” at an A-weighted sound level of 75 dB at 100 feet is in fact “clearly audible” — at least to pedestrians — under unspecified circumstances. The requirement for a warning “horn or whistle” capable of producing a sound level 10 dB higher is presumably intended to warn motorists at grade level crossings. This 10 dB differential is evidently viewed as sufficient to overcome the roughly 30 dB acoustic insertion loss of motor vehicles of recent manufacture, and to produce an adequate signal-to-noise ratio with respect to the interior (driver- controlled) sound environment of motor vehicles. 2 The literal requirement for “horns”, “bells”, and “whistles” on light rail vehicles is loosely interpreted as permitting a variety of front-mounted, electrically-activated warning signals rather than the usual top-mounted, high pressure air horns generally installed on federally-regulated heavy rail locomotives.

13 General Order 143-B is silent about a technical rationale to support the requirements of §3.04. However, this rationale presumably includes tacit assumptions not only about issues of warning effectiveness, but also about commonly encountered urban and automobile interior ambient noise environments, typical spectral content of warning devices, the manner of activation of warning signals for light rail vehicles, and adverse community reaction to excessively loud horns, bells, and whistles. These assumptions are unlikely to be met in at least some circumstances of current interest, because they are not directly linked to the acoustic determinants of warning signal effectiveness: the bandwidth-corrected signal to noise ratio of the warning signal at the listener’s ear. An A-weighted sound level for a warning signal does not constrain the frequency composition of the signal, and has nothing whatever to do with the influence of background noise levels on warning signal audibility. Related Federal Regulatory Requirements 49 CFR Ch. VI §659.21 delegates oversight responsibility for safety-related matters of intra-state transit agencies to individual states. Even though the provisions of the Federal Railroad Administration’s 49 CFR Ch. II §229.129 apply to interstate freight rather than transit systems, however, they are of at least passing relevance to current concerns. The first paragraph of this three-paragraph-long section requires only that a lead locomotive must be “provided with an audible warning device that produces a minimum sound level of 96 db(A) (sic) at 100 feet forward of the locomotive in its direction of travel.” This language is usually interpreted as applying to an as-installed condition, although it could arguably be interpreted as applying to the audible warning device itself. Manufacturers often claim that air horns marketed as audible warning signals for locomotives produce A-weighted levels considerably (15 dB or more) higher than the regulatory minimum. The acoustic measurement provisions of the remaining two paragraphs of §229.129 permit compliance with the nominal requirements of the first paragraph by warning signals about 5 dB lower in level than nominally specified. Paragraph (b) permits measurements of sound levels of locomotive warning signals to be made with a non-precision, Type II sound level meter. Paragraph (c) further states that “A 4 dB(A) measurement tolerance is allowable for a given measurement.” ANSI S1.4, “Specification for Sound Level Meters”, permits a tolerance of  1.5 dB in Type II meters in the mid-frequency range that generally contains the greatest concentration of energy emitted by train horns. To this tolerance must be added the tolerance of the field calibrator, which can be as great as  0.3 dB. Thus, the true A-weighted sound level produced by a train horn that meets the nominal requirements of §229.129 may be as little as 90.2 dB at 100 feet. According to Lipscomb (2001), the mean A-weighted sound level in 71 measurements of installed train horns at a distance of 100 feet in front of locomotives was 100 dB. In reality, compliance with the requirement of 49 CFR Ch. II §229.129 guarantees nothing about the actual warning effectiveness (or even the audibility) of a train horn, because the audibility of a warning signal is determined by its frequency content relative to that of the masking (outdoor ambient or vehicle interior ) noise in which it occurs. 49 CFR Ch. II §229.129 is also silent on the mounting position for warning devices on the locomotive, the manner of activation of the locomotive warning signal, and on the matter of adverse community reaction to frequent warning signals. The terrain, geometry, and land uses along the approach to a grade level crossing, the speed of a train at the crossing, the composition and volume of the cross traffic, the ambient noise environment in the vicinity of the crossing, and even the frequency of use of the rail crossing can all affect the effectiveness and community annoyance of train-mounted audible warning signals. Thus, the same audible warning signal that is adequate to alert a few pedestrians to the hazards of slow- moving trains at crossings with unobstructed visibility and low ambient noise levels may be ineffective in alerting truck traffic to the hazards of collisions at grade level crossings in busy intersections in noisy,

14 built-up industrial areas with short lines of sight along rail rights of way. By the same token, audible warning signals that annoy few people when sounded once or twice a day in low population density areas may be major irritants when sounded many times an hour in high population density neighborhoods. Other Standards for Warning Signal Effectiveness Audible warnings are commonplace in industrial, occupational, recreational, residential, military and other applications as diverse as back-up alarms for construction equipment; low vision street crossing aids; automotive signaling; maritime navigation; aviation, nuclear power plant and other critical operational settings (as varied as mining, quarrying, blasting, electrical distribution, radiological, overhead crane and elevator operation, and motor sports applications); indoor and outdoor emergency evacuation, public safety, and civil defense signals; medical electronics; fire and burglar alarms, and so forth. However, no industrial or statutory standards for warning signal effectiveness of transportation sources (including 49 CFR Ch. II §229.129) are directly applicable to alerting pedestrians to the hazards of light rail grade level crossings. Furthermore, statutory requirements and other standards for audible warning signals typically offer only little or no quantitative guidance about their design and operation. The provisions of Chapter 5 (“Horns and Emergency Warning Signals”) of the Indiana state code (IC 9-19-5-1) are typical, in that they simultaneously require that warning signals for motor vehicles be “capable of emitting sound audible under normal conditions from a distance of not less than two hundred (200) feet”, and that such a “horn or other warning device may not emit an unreasonably loud or harsh sound or whistle.” Similarly, a proposed national fire alarm standard (Swets and Green, 1975) suggests only that a two tone (high-low, or “continental”) alarm is appropriate for outdoor signaling by all moving vehicles. No standard explicitly describes a quantitative criterion of warning signal effectiveness, nor provides a systematic rationale for prediction of community reaction to such signals. Primary Empirical Research on the Effectiveness of Transportation-Related Audible Warnings Surprisingly few controlled tests of the effectiveness of vehicular warning signals have been published in peer-reviewed journals. This dearth of original research is probably due in part to the number and complexity of factors that affect warning signal effectiveness in real-world settings. Although a large part of the problem of assessing warning signal effectiveness is acoustic in nature, another part, at least as important, is the phenomenon of divided attention. A great deal is understood about the ability of attentive observers to correctly report the presence of acoustic signals heard in broadband noise (cf. Green and Swets, 1966). Much less is understood about the ability of acoustic signals to distract attention from ongoing foreground tasks. Little useful quantitative guidance about human performance in divided attention situations is applicable to everyday performance of real-world tasks. On the one hand, it is well known that human hearing is closely coupled to attentional mechanisms. Meaningful sounds of very low signal-to-noise ratio (a footfall or a whisper in a bedroom at night, a key turning in a lock, and a snapping twig in a forest) can serve to alert or even startle people. On the other hand, people whose attention is closely focused elsewhere (e.g., on a cell phone conversation or listening to a walkman), or who are otherwise engrossed in cognitive tasks other than listening for warning signals, may fail to heed repeated auditory and visual warnings, even at high signal-to-noise ratios. No purely acoustic analysis of warning signal effectiveness reflects the full range of variability in human performance in processing warning signals. The following four papers illustrate the range and types of theoretical and empirical approaches most directly relevant to estimating acoustic warning signal effectiveness. Corliss, E.,and Jones, F. (1976) “Method for estimating the audibility and effective loudness of sirens and speech in automobiles”, J. Acoust. Soc. Am., Vol 60, No. 5, 1126-1131.

This theoretical paper estimates from first principles the signal-to-noise ratios necessary for a sinusoid in noise to command attention. Corliss and Jones assume that “a fair criterion for the ability of an emergency vehicle siren to attract attention might be the requirement that it should produce for the driver the loudness sensation equivalent to a signal of 65 dB presented in the quiet”. They continue from this assumption to reason that for an emergency vehicle’s warning signal to attain a speech-like level of about 72 dB inside a quiet car, its outside level must exceed 100 dB, considering the nominal 30 dB acoustic insertion loss of a car in the frequency range of typical interest. Corliss and Jones present no empirical tests or demonstrations of warning signal effectiveness to confirm their analysis, however. Fidell, S., (1978) “Effectiveness of audible warning signals for emergency vehicles”, Human Factors, 20(1), 19-26. Fidell (1978) is the most commonly cited controlled empirical study of the effectiveness of transportation-relevant audible warning signals.3 Fidell exposed 24 drivers of an instrumented test car in a laboratory setting to six warning signals from a loudspeaker in the back seat that reproduced both the emergency vehicle signals and road noise. The presentation levels (and hence, signal-to-noise ratios) of the randomly-timed warning signals were increased until test subjects interrupted an ongoing, simulated driving task by taking their feet off the accelerator pedal and braking, as instructed upon notice of a warning signal. The average level of audibility at which warning signals distracted attention from the ongoing driving task was characterized by a d’ level of 37. The quantity d’ is a scalar (dimensionless) unit of signal detectability that reflects the bandwidth- adjusted signal-to-noise ratio of a signal in the presence of background noise. Green and Swets (1966) derive and discuss the theoretical basis for quantifying human signal detection performance under conditions of uncertainty and risk. Detectability (d’) is the ability to detect a signal in the presence of noise, quantified by the bandwidth adjusted signal-to-noise ratio: where η is the efficiency of a human detector relative to an ideal energy detector (assumed to be 0.4 for a reasonably attentive human observer); ∆fi is the bandwidth of the ith one-third octave band; si is the sound pressure of the signal in the ith one-third octave band; and ni is the sound pressure of the noise in the ith one-third octave band. The quantity “Detectability Level”, or (D’L), is the decibel equivalent value of d’, or 10 log d’. Figure 1 is a nomogram that may be used to determine from one-third octave band sound levels of both signal and noise when a signal attains a level of detectability characterized by a d’ value of 2.324. The figure, a graphic representation of the terms of the above equation, is used by plotting the signal levels in one-third octave bands on the perpendicular axes, and the 3 This research, sponsored by the Society of Automotive Engineers, has also been reported in other technical documents (e.g., Skeiber, Mason, and Potter, 1977) and in the trade press. 15 4 A d’ level of 2.32 is sometimes considered a nominal threshold of audibility, since it represents a level of decision- making performance at which the presence of a signal is correctly reported 50% of the time at a 1% false alarm rate.

background noise levels with respect to the slanted lines. As plotted in Figure 1, a signal must attain a level equal to the noise in some frequency region for its audibility to reach a d’ value of 2.32. Visual comparisons of signal-to-noise ratios in each one-third octave band can identify the frequency region(s) that contribute most strongly to overall signal detectability, as well as the magnitude of any changes necessary in signal (or noise) level to reach a d’ value of 2.32. Figure 1 Nomograph for determining when an acoustic signal is just audible 16

[p(hit) = 0.5, p(false alarm) = .01] in broadband noise. The average d’ value of 37 that was observed by Fidell (1978) is 12 dB greater than a nominal threshold of audibility (d’ =2.32), and approximately 10 dB greater than the d  value (4.0) at which people can correctly detect an acoustic signal 95% of the time with a 1% false alarm rate. In other words, the data of Fidell (1978) show that an effective warning signal — one noticeable enough to distract attention from an ongoing task other than attentive listening for warning signals—must on average attain a signal-to-noise ratio an order of magnitude (10 dB) greater than one which is merely reliably detectable (d’ = 4, or D’L = 6)) by an attentive listener. However, the level of audibility of a warning signal that would invariably come to the attention of all observers, regardless of attentional state, would obviously have to be higher yet. Fidell, S. and Teffeteller, S., (1981) “Scaling the Annoyance of Intrusive Sounds,” J. Sound Vib., Vol. 78, No. 2, 291-298. Fidell and Teffeteller conducted a controlled laboratory study under free-field listening conditions of the “intrusiveness” of noises to ten test subjects whose attention was absorbed in a video game. A computer varied the levels of a set of ten signals (household appliances and power tools) in a method of limits protocol, each sequence separated by unpredictable waiting periods of several minutes. Steps were presented in a staircase of 2 dB increments each 20 seconds long, and continued until they distracted attention from the video game sufficiently for a test subject to signify their notice by pressing a button. At the level at which test signals were sufficiently noticeable to be considered intrusive (not necessarily the same level at which they were first noticed), test subjects were also asked to judge whether they were “slightly”, “moderately”, “very”, or “extremely” annoying. The average A-weighted level at which the test signals were noticed in a PNC-40 background noise environment was 48 dB. Their corresponding average detection level (D’L) was 14.2. Figure 2 shows the relationship between the audibility of intrusive signals (expressed in decibel- like D’L units) and mean annoyance ratings inferred from the data of this study. Very few sounds were judged highly (“very” or “extremely”) annoying at a level of audibility at which virtually everyone would be expected to notice them (d’ = 316, D’L = 25). Although this is an encouraging finding with respect to the potential community annoyance of auditory warning signals from light rail vehicles, it is based on a limited amount of information from a single laboratory study of modest size. Figure 2 Least squares fits to cumulative distributions of the judge annoyance of intrusive sounds. 17

Sneddon, M., Pearsons, and Fidell, S., (in press) “Laboratory study of the noticeability and annoyance of sounds of low signal-to-noise ratio”, Noise Control Engineering Journal. Sneddon et al. measured the levels of detectability at which fifteen acoustic signals (two aircraft flyovers, and car, truck and commuter rail vehicle passbys, as heard at four distances) reliably attracted the attention of ten test subjects engaged in an activity other than specifically listening for such a sound. The subjects, who were seated in an anechoic chamber while reading materials of their own choosing were asked in a free-response protocol to note the occurrence of sounds presented at relatively low signal-to-noise-ratios in natural-sounding but highly constrained background noise environments. A logistic fit to the findings (shown in Figure 3) indicated that a detectability level considerably greater than that needed for essentially perfect attentive detection (D’L = 6) was required if substantially all signal presentations are to be noticed. Figure 3 Detection levels of sounds at which test subjects failed to notice various proportions of signal presentations. Secondary Literature On Audible Warnings in Grade Level Rail/Street Traffic Accidents No primary research on the noticeability of transportation-related warning and other sounds apart from that described above was found in English-language, peer-reviewed journals. A modicum of analytic and case-study work has, however, been undertaken in occupational settings (e.g., Patterson, 1982; Sorkin, 1987). Much of the rest of the oral presentations, symposium proceedings, handbook chapters, and technical reports germane to the present concern is comprised of non-empirical studies, anecdotal discussions, and oft-repeated cautions about the inability of locomotive-mounted horns to prevent automotive collisions with trains at grade level rail crossings. A number of typical references of this sort are summarized in the following sub-sections. 18

19 Abrams, B.S., and Lipscomb, D.M. (1996) “Visual and auditory correlates in rail crossing safety”, Presented at Fourth International Symposium on Railroad-Highway Grade Crossing Research and Safety, 8-10 October, 1996, Knovxville, TN. The bulk of this three part presentation is an academic discussion of basic human sensory and perceptual capability, with only tenuous linkages drawn to specifics of sensory function or signal requirements in actual grade crossing settings. The authors conclude that better understanding of human perceptual capabilities can “contribute to better safety policies and equipment”. The presentation makes a number of points about the audibility and noticeability of warning signals that are not directly relevant to issues of warning signal effectiveness. It notes, for example, on page 20 that “Most young, non-pathological ears can detect a 6.5 dB sound pressure level (SPL) at frequencies in the range of greatest sensitivity...(in the range of 2.5 kHz to 3 kHz)”. This information is tangential at best to present concerns, because it has little to do with the practical audibility of train horns. Train horns, which may not radiate strongly in the frequency range of greatest human sensitivity in any event, are typically produced and must be detected in background noise at levels many orders of magnitude higher. Further, the relevant issue for audibility and effectiveness of warning signals is not the absolute sensitivity of human hearing, but the frequency region of the greatest effective signal-to-noise ratio at a listener’s ear. The concept of a unique, fixed auditory detection threshold (“now you hear it/now you don’t”) has also been outmoded since the 1960s, as recognition of the probabilistic nature of acoustic signal detection under real-world conditions of uncertainty and risk has become universal. The authors do not distinguish carefully between an absolute sound pressure level and what they term an “alerting threshold” of 9 to 10 dB above the background or ambient sound level. The figure of “9 to 10 dB” that Abrams and Lipscomb cite is an increase in audibility above a detection level of d' = 4, not an A-weighted or an octave band differential in absolute signal level. The detection index d' is a measure of bandwidth-corrected signal to noise ratio, customarily calculated for warning signal analyses in one-third octave bands. An effective warning signal — that is, one noticeable enough to distract attention from an ongoing task — is not necessarily “twice as loud as competing sounds”, as Abrams and Lipscomb assert. The Appendix to the document mis-states the requirement of 49 CFR 229.129 for a minimum A- weighted sound level of a locomotive-mounted warning device as 95 decibels. Lipscomb, D.L. (1993). “Audibility of train horns and crossing accident investigation techniques.” Proceedings of Second International Symposium on Railroad-Highway Grade Crossing Research and Safety, Transportation Center, The University of Tennessee, Knoxville, TN. This introductory-level presentation notes the deleterious effects of the acoustic insertion loss of automobiles on the audibility of locomotive warning horns, and concludes with an appeal for a non-acoustic alternative form of warning signal. The presentation does not develop the recommendation for such a device beyond a conceptual level. Lipscomb, D.M., (1996) “Train horns seem so loud: So why don’t motorists hear them sometimes?”, Presentation made at Fourth International Symposium on Railroad-Highway Grade Crossing Research and Safety, 8-10 October, 1996, Knoxville, TN. This oral presentation reiterates familiar aspects of the conventional source-path-receiver approach to analysis of the audibility of acoustic signals. The author cites common factors that can affect warning signal source levels (including make, model, age, maintenance, placement, orientation and activation of the train horn); factors that can affect propagation of sound from a

20 locomotive horn to a driver approaching a grade level crossing (such as terrain, atmospheric conditions, barriers, and vehicle insertion loss); and masking noise levels. No mention is made of the attentional state of the listener. The discussion presents no new research findings, and is general and largely non-quantitative in nature. It lacks specifics that would assist in prioritizing the importance of the various factors mentioned in passing, and criteria for warning signal effectiveness. The author concludes only that “myriad combinations” of factors influence audibility of train locomotive horns, and that their audibility in some circumstances does not imply their audibility in others. Lipscomb D.M. (2001) “Measured sound output of locomotive horns”, Presentation made at Sixth International Symposium on Railroad-Highway Grade Crossing Research and Safety, October 17-19, Knoxville, TN. This oral presentation repeats many of the points made by the author in his 1996 presentation at the same symposium, while presenting summary information about 71 measurements of A- weighted sound levels produced by train horns 100 feet in front of the locomotive. The mean measured sound level rounds to 100 dB, with a standard deviation of 6.8 dB. The author notes that the median measured level (99 dB) is about 14 dB lower than the manufacturers’ advertised specifications, but still 3 dB greater than the Federal Railroad Administration’s regulatory requirement of 96 dB (49 CFR 229.129). The author notes that some percentage of the measured levels fall below the regulatory minimum, but fails to acknowledge the 4 dB testing tolerance allowed in CFR 49 229.129. The conclusions suggest attention to installation-specific factors (placement, orientation) of train horns and confirmation of as-installed sound levels, rather than increased source levels, as a preferred compliance measure.

21 CONSIDERATIONS FOR PERSONS WITH DISABILITIES The use of auditory directional icons may be particularly useful assisting visually impaired pedestrians locate potential threats at level grade crossings. The use of a visual iconic direction LED sign may be particularly helpful in assisting hearing-impaired pedestrians locate the direction of potential threats at grade crossings. The use of both directional warnings may reinforce each other in persons with some vision or hearing loss. Traditional bells and horns may not effectively meet the requirements of either population. A system to meet the needs of the impaired may also indicate when it is clear to cross. In order to address the needs of an impaired traveler, it may be more cost effective to adopt a new system, which meets their needs, while at the same time improving the safety of the non-impaired traveler. Optimizing the efficacy of non-directional bells and beacons may not meet either goal. Legal blindness is defined as best corrected acuity (central vision) in the better eye of 20/200 or worse, and/or a visual field (peripheral vision) of 20 degrees or less. In actual fact, the definition of severe visual impairment as used by the National Center for Health Statistics is inability to read newsprint even with normal correction; a definition that suggests that severe visual impairment corresponds to a best corrected visual acuity of 20/50. To place this in some context, a visual acuity of 20/50 would, in addition to severely limiting reading and many activities of daily living, prevent an individual from obtaining a driver’s license in most states (Goodrich, 1995). Many large, population-based, cross-sectional studies have documented the increase in prevalence of eye disease and visual impairment with increasing age, particularly in persons over the age of 75 (Haegersrtrom-Portnoy, Schneck and Brabyn, 1999). It is estimated that in the U.S. more than 26 million people over the age of 40 are affected with some type of visual disorder and that more than 4 million individuals in the U.S. aged 55 or older are currently experiencing severe vision loss (U.S. Department of Veterans Affairs, 1999). Moreover, The National Eye Institute (2001) recently estimated that in the U.S. over 1.1 million people are legally blind. Prevalence rate estimations of visual impairment per 1,000 persons in the U.S. clearly demonstrate the significant increase in vision problems with age. Because vision impairment touches the lives of the majority of middle-aged and older adults either through personal experience, that of a family member, or of someone else in their social network, it represents a major health issue for Americans (Watson, 2001). Moreover, the economic implications surrounding this disability are considerable. A recent study has suggested that direct and indirect costs related to blindness and visual impairment total approximately $38.4 billion annually (NEI, 2001). Perhaps the most significant cost of visual impairment is the personal reduction in independence and diminished functional ability that often arises as a result of vision loss. The effects of visual impairment in reducing an individual’s ability to drive and travel independently are often pointed to as expected outcomes following severe vision loss, yet other issues such as management of personal finances, correspondence, and other important daily activities also may prove extremely problematic because of visual impairment (Goodrich, 1995). In order for visually impaired individuals to cross streets independently, they must be able to recognize that they have arrived at an intersecting street; determine the configuration of the intersection so that they can establish an optimal location, heading, and procedure for crossing. It is also helpful to be able to determine or confirm the name of the intersecting street. When intersections are familiar, some of this information may already be known. Much of this information is typically obtained by listening to traffic patterns and sounds of individual vehicles (Jacobson, 1993; LaGrow & Weessies, 1994; Blasch, Wiener & Welsh, 1997). Techniques and cues used in crossing streets are diverse and vary by location and individual. Many visually impaired pedestrians have received mobility instruction from an orientation and mobility specialist to use a cane and/or dog guide to travel independently. In the most common technique utilized for crossing at signalized intersections, pedestrians who are blind begin to cross the street when there is a surge of traffic parallel to their direction of travel. Vehicular sounds are often sufficient to determine the onset of the WALK interval and the direction to the crosswalk on the opposite side of the street. However

22 due to some intersection geometry, acoustic conditions, and traffic control systems it is very difficult if not prohibitive for persons who are visually impaired to determine the cues necessary to cross streets independently and safely. These problems of safe street crossing are generally made even more difficult for elderly visually impaired individuals with the additional functional limitations of reduced hearing, slower and in some cases an unsteady gait, ability to process information and response time to mention a few. Despite the difficulties presented above, a large number of travelers who are blind cross streets safely and independently. This attests to their ability to apply principles and skills for street crossing which have continued to evolve with the growth of the field of Orientation and Mobility. These principles and skills are based on acquiring the necessary information through limited vision or other sensory modalities. Nonetheless, there are many intersections that blind individuals consider to be unsafe for crossing without the assistance of a human guide. Individual differences in impairments, skills, abilities, and personality as well as the environmental situation determine which streets any individual will choose to cross independently. Since the 1940s, when organized instruction in independent travel for individuals who are blind began, there have been many changes to intersection configurations, traffic control systems and technology, and in vehicular traffic in general. Many of these changes have made crossing streets much more difficult if not prohibitive for persons with visual impairments. Where traffic is abundant on all streets at an intersection, it is usually possible for travelers who are blind to determine whether vehicular traffic on streets is controlled by stop signs or traffic signals. Further, where intersections are traffic signal controlled, it is often easy to determine which street has the right of way. Nonetheless, delayed or prolonged green lights, separate turning signals, and permitted right turns on red lights after stopping make it difficult to determine traffic control patterns at many intersections. Even if one understands the traffic control at an intersection, it may still be difficult to determine a safe time to initiate a crossing. Particularly difficult and hazardous are intersections with fast but intermittent traffic, in which it is difficult to determine the onset of parallel traffic. Intersections in which there is a designated pedestrian crossing cycle present particular challenges, especially if all traffic is stopped during that cycle. While such signals often provide the only safe time for any pedestrian to cross, any situation in which there is not audibly idling traffic on all streets at an intersection there is insufficient auditory information for blind travelers. In this instance, the individual may not know whether there is simply no traffic on one street (for what could be a very short moment), or whether the pedestrian cycle has begun. Where pedestrian crossing cycles are pedestrian activated, it may be difficult for persons who are visually impaired to locate the activating button (Peck & Uslan, 1990; Bentzen, Barlow & Franck, 2000). Where all traffic is stopped during a pedestrian crossing cycle (scatter light), it may not only be difficult to determine the onset of the pedestrian cycle, but also to maintain a straight line of travel toward an opposite up curb because of the unpredictability of pedestrian travel directions. Traffic signals that are dynamically adjusted by volume of traffic flow (actuated) are particularly difficult for blind travelers because it is not possible to determine with any certainty when and for how long pedestrian cycles or parallel traffic cycles will occur. Accessible Pedestrian Signals are classified into three types. The first type of signal uses mounted speakers that sound like some kind of bell, buzz, birdcall or melody, and most can be heard by anyone in the vicinity. A second type of Accessible Pedestrian Signal uses a transmitter or as an example, a remote infrared signage technology as used by Talking Signs™ and Relume™. This approach, as used at a number of intersections in San Francisco, uses recorded speech to tell users “Walk” or “Wait.” Messages which are audible only to users, and only when users are standing at a crosswalk, are heard by means of small receivers when the receivers are activated by users. As users approach corners, they can also receive messages telling them the name of the intersecting street, the parallel street, which block they are on (for example, 100 block), and which direction they are traveling. This type of device also has the capacity to provide messages that could also be used to describe intersection configuration and/or the traffic control system. The third type of Accessible Pedestrian Signal is a sound generator and

23 vibrating hardware which are integrated into the pedestrian push button. Audible push button locating signals are heard from the near vicinity of the push button, and a different message or repetition rate is used to indicate the WALK interval. Research on auditory pedestrian signals has yielded a number of significant findings indicating the advantages to visually impaired pedestrians, along with the drawbacks resulting from the use of these signals. Some of the advantages include, improved discrimination between the WALK and DON’T WALK indications, and a decrease in the time to align and complete the crossing (Stevens, 1993; Oliver, 1989). Stevens found that alternating audible pedestrian signals proved to be superior to non-alternating signals in helping blind pedestrians remain within the crosswalk. Although such signals provide notable advantages, problems exist such as difficulties localizing the sounds emitted, and the masking of the signal under noisy or high traffic conditions (Stevens1993; Oliver, 1989). Furthermore, these problems are exacerbated for seniors because hearing declines markedly as people age. Such difficulties may cause pedestrians to be unclear which leg of the intersection is safe to cross, and where exactly the opposite end of the crosswalk is located. Such shortcomings may lead to a false sense of security, which could lead to serious consequences. Although little research has compared the relatively effectiveness of different commercially available accessible signals produced for persons with no vision, limited research has examined ways of assisting the larger portion of the blind community with some usable vision. One study by Van Houten, Blasch, and Malenfant, examined whether the addition of the animated eyes display used to remind sighted pedestrians to watch for turning vehicles helped blind persons with low vision to discriminate the WALK sign. The results of this study showed that low vision blind persons could identify the WALK signal 50% further when the eyes were included. This study was conducted under laboratory conditions and should be replicated under field conditions. It is essential to compare the efficacy of these new emerging technologies in order to determine which ones best meet the needs of the elderly population with visual impairment. None of the research to date addresses this question. As stated above, the number of older individuals experiencing vision loss and other disabilities is expected to grow in the coming decades (Crews, 1991; Pope & Tarlov, 1991; Manton, Corder & Stallard, 1993). Gerontological research has focused on identifying risk factors for the development of disability in terms of personal care tasks, (ADLs), and tasks considered essential for social independence, (IADLs) (Kovar & Lawton, 1994). This research has led to the recognition that successful performance of ADLs and IADLs involves multiple domains, of which mobility may be the single most important (Verbrugge, Gruber-Baldini & Fozard, 1996). Related measures, such as assessments of whether persons can independently leave their homes, go outdoors, and use transportation, have identified persons in need of assistance with ADLs (Clark & Maddox, 1992) suggesting that mobility limitation may, in fact, precede the development of difficulties in specific ADL and IADL tasks. For the visually impaired traveler, the already difficult and dangerous task of safely traveling in cities is becoming even more complicated and hazardous. The right-turn on red law, as well as the increasing production of quieter running cars have made the use of traffic sounds more difficult, particularly for the visually impaired pedestrian. A major impediment to effective and safe street crossing for visually impaired travelers is the increasing use of traffic signals that are dynamically adjusted (actuated) by the volume of traffic flow. Because of these actuated traffic signals, the visually impaired traveler is not able to determine with any certainty when and for how long the ‘WALK’ signal will occur. In response to this problem, the Transportation Equity Act for the 21st Century was passed in January of 1998 (H.R.2400). This Act specifies that safety considerations shall include the installation, where appropriate, and maintenance of audible traffic signals and audible signs at street crossings. However, there has been only limited evaluation of these different signals, and to date only one study has attempted to compare their effectiveness (Blasch, 1999). Although efforts have been made to develop

24 Accessible Pedestrian Signals for the totally blind traveler, little attention has been paid to the problem of developing more effective visual signals for the partially sighted individual. The paucity of research in the area of visual signals for individuals with low vision is particularly problematic considering that over 80 percent of the legally blind veteran population has some remaining vision (De l’Aune, Williams & Welsh, 2000). There has been limited research testing Accessible Pedestrian Devices (Bentzen & Tabor, 1998; Bentzen, Crandall, Chigier, Warden & Carosella, 1995; Crandall, Brabyn, Bentzen & Myers, 1998; Crandall, Bentzen, Myers & Mitchell, 1995; Department of Transport, 1993; Hall, Rabelle & Zabihaylo, 1994; Huscher, 1976; and Van Houten, Malenfant & Van Houten, & Retting,1997). The studies that have been done compared a specific Accessible Pedestrian Device (e.g., Talking Signs) to no signal. In one case, Hall, Rabelle & Zabihaylo used one Accessible Pedestrian Device and tested a variety of presentations and locations of the sound sources. Unfortunately, there has been very limited research to evaluate Accessible Pedestrian Signals for individuals with low vision. Van Houten, Blasch, and Malenfant have evaluated a modification to the Relume™ Accessible Pedestrian signal that included animated eyes documented to improve the safety of sighted pedestrians by prompting them to look for turning vehicles (Van Houten, Retting, Van Houten, Farmer, & Malenfant, 1999). The study by Van Houten, Blasch, and Malenfant found that low vision blind pedestrians could identify the shape of the WALK indication from 50% further away when it included the animated eyes display. These results showed that the addition of an animated ‘eyes’ display to the WALK sign significantly improves recognition distance for a large segment of persons with visual impairment. It should also be noted that none of the participants miss-identified the WALK indication with the ‘eyes’ as the DON’T WALK indication or the DON’T WALK signal as the WALK with the ‘eyes’ display. However, many of the participants identified the ‘WALK’ symbol without the eyes as the ‘DON’T WALK’ indication, and the DON’T WALK signals as the standard WALK indication on some of the trials. These data suggest that using the WALK signal with the animated eyes could reduce the frequency of pedestrians with low vision inadvertently crossing against the signal. Although these findings are promising, they need to be replicated under field conditions with a larger pool of low vision participants, as proposed in this research study. Preliminary research has shown that low vision pedestrians and totally blind pedestrians can be assisted by Accessible Pedestrian Signals. These data also show that although all currently produced Accessible Pedestrian Signals are useful to some degree to persons with a visual impairment, two of the signals (the ReLume™ and Talking Signs™) show particular promise in also providing a line of direction for street crossing. Blasch compared 8 different Accessible Pedestrian Signals installed along a major intersection located in the city of Decatur, Georgia during the meeting of the Southeastern Orientation and Mobility Association (SOMA) in March of 1999. Findings from this pilot study indicated that there were no significant differences between the different Accessible Pedestrian Signals regarding the confidence and comfort of the traveler between the 8 different devices. There was, however, a significant difference found between the eight Accessible Pedestrian Signals regarding their utility in providing a line of direction for the street crossing. The two pedestrian signals that were shown to significantly enhance traveler directional orientation were the ReLume™ and Talking Signs™ signals. This finding has practical significance, particularly in light of the fact that several studies have reported that individuals who are blind have difficulty staying within the crosswalk lines, as no non-visual cues are ordinarily present to provide assistance (Bentzen, Barlow, & Franck, 2000). Veering out of the crosswalk into the intersection is a particularly dangerous pedestrian travel event to which the ReLume™ and Talking Signs™ signals attempt to address. Finally, the authors have been unable to find any study that directly compared the effectiveness of the different Accessible Pedestrian Signals in normal traffic conditions other than the 1999 pilot study conducted by Blasch. The paucity of scientifically rigorous research which evaluates the efficacy of various Accessible Pedestrian Signal devices is a serious limitation to extend knowledge on this critical area of visual impairment rehabilitation and policy.

25 Far more neglected is the research in the area of deaf and hearing impaired related to Pedestrian Signals. Because of the lack of research in the Light Rail Transit Environments for the visually impaired and hearing impaired, information has been presented in a similar area involving Accessible Pedestrian Signals. The following summary of selected studies provides background on additional studies conducted on accessible design: Accessible Pedestrian Signals: Synthesis and Guide to Best Practice (2003). NCHRP Research Results Digest, Transportation Research Board This digest summarizes the publication "Accessible Pedestrian Signals: Synthesis and Guide to Best Practice," by J.M. Barlow, B.L. Bentzen and L. Tabor of Accessible Design for the Blind. Following an introduction and background information on accessible pedestrian signals (APS), the digest covers the following topics: U.S. rules and regulations related to APS; international practice; APS technologies and features; where to install APS; designing installations; new construction or reconstruction installation; retrofitting an intersection with an APS; and specifications for installation of APS components. Arnold, ED, Jr; Dougald, LE. (2003). Guidelines For The Retrofit Installation Of Accessible Pedestrian Signals By The Virginia Department Of Transportation: Phase I Report. Virginia Transportation Research Council, Virginia Department of Transportation. In late 2000, the Northern Virginia District of the Virginia Department of Transportation (VDOT) received a request from a visually impaired citizen to install accessible pedestrian signals (APS) at an intersection in Falls Church. Since there were no national or state guidelines for this type of installation, the district was requested to install APS at an intersection as a pilot and develop appropriate guidelines that could be used statewide by VDOT for future installations. The Virginia Transportation Research Council was asked to assist in developing the guidelines. Further, a committee composed of representatives from VDOT, the Federal Highway Administration, the Virginia Department for the Blind and Visually Impaired, and the blind/visually impaired community (both formal organizations and individual citizen activists) was established to provide overall guidance and advice. The guidelines will be applicable to retrofit installations and will ultimately include the following sections: (1) a procedure for requesting APS, (2) the basic requirements for retrofit, (3) an intersection evaluation methodology, (4) a funding process, (5) the basic specifications for APS equipment to be used statewide, and (6) installation guidance. As of April 2003, the first four of these sections were finalized. The aforementioned committee recommended that VDOT undertake a 2-year pilot to field test the application of these four sections while the evaluation of the piloted equipment was being completed and the final two sections were being developed. This Phase I report describes the background for the pilot project, its purpose and scope, the methods undertaken, and the results to date that led to the recommendation for the 2-year pilot. Specifically, the report includes details on the following: (1) Results of a survey of VDOT's district traffic engineers. No APS have been installed at VDOT-maintained intersections and only a handful of cities have installed them. (2) Results of a review of the literature. The APS guidelines from the Committee for the Removal of Architectural Barriers; the Los Angeles Department of Transportation; Fountain Valley, California; and Portland, Oregon, are described. (3) Timeline of key events in the development of the guidelines. The timeline focuses on the committee's review and role and traces the drafting of the 10 iterations before the final guidelines were accepted and approved. (4) Outline of the guidelines. A final outline of the guidelines is provided, and Sections I through IV are presented in an appendix. Forms for requesting an APS retrofit and for evaluating intersections are also included in appendices. The report concludes with a discussion of the next steps, or tasks, that are required to complete the guidelines.

26 Bentzen, BL; Barlow, JM; Tabor, LS, (2000). Detectable Warnings: Synthesis of U.S. and International Practice. U.S. Access Board This synthesis summarizes the state-of-the-art regarding the design, installation and effectiveness of detectable warning surfaces used in the U.S. and abroad. The need for a warning surface is documented. U.S. and international research on detectable warnings is reviewed. U.S. and international standards and guidelines for detectable warnings are presented. Use of detectable warnings in the U.S. and abroad is described, with illustrative case studies. Information is provided on U.S. detectable warning products and manufacturers. Jurisdictional recommendations for the use of truncated dome detectable warnings are summarized and illustrated. The synthesis will be helpful to transportation engineers, planners, and other interested persons working to make public rights-of-way more accessible to people who have visual impairments. Bentzen, BL; Crandall, WF; Myers, L. (1999). Wayfinding System for Transportation Services: Remote Infrared Audible Signage For Transit Stations, Surface Transit, and Intersections. Transportation Research Record, Issue1671. People who are print-disabled, who are blind, or who have other visual impairments are restricted in their ability to participate in public life because of lack of labels and signs in the environment. Currently, persons with severe visual impairments often require extensive assistance from strangers to travel in unfamiliar areas. Many other types of disabilities can prevent people from reading print. In addition to people who are blind or who have low vision, there are many head- injured, autistic, and dyslexic (or even just educationally impaired) people, along with persons who have had a stroke, who are not able to assimilate printed language even though they can see the page. Many people can accept the information through speech--that is, having print read aloud to them. Some human factors evaluations of a signage system specifically developed to aid people who have visual impairments or a print-reading disability gain information that is available to sighted people through print are described in this paper. This remote, infrared audible signage system--Talking Signs--is composed of a small infrared transmitter that emits a repeating voice message over a directional light beam to a handheld receiver carried by the blind pedestrian. The infrared system greatly reduces the need for travelers to remember distances, directions, and turns, thereby enhancing independence and efficiency in travel. Results show that remote infrared audible signage provides effective wayfinding information for using transit stations, surface transit, and intersections, thereby enhancing independent use of public transit by people who have visual impairments or cognitive disabilities. Bentzen, BL; Tabor, LS. (1998). Accessible Pedestrian Signals. Accessible Designs for the Blind. Architectural and Transportation Barriers Compliance Board The Transportation Equity Act for the 21st Century - TEA-21, the successor to ISTEA - directs the pedestrian safety considerations, including the installation of audible traffic signals, where appropriate, be included in new transportation plans and projects. The bill was signed into law on June 9, 1998. Blasch, B., Templer, J., and Zimring, C. (1989). Visually Impaired People - Design for Safety, Information and Orientation. Encyclopedia of Architecture. This article deals with design of the built environment to facilitate the accessibility and travel for individuals with a visual impairment. The use of design features to serve as landmarks for individuals with a visual impairment was also discussed. The intent of this article was to suggest the consideration of designing to facilitate wayfinding for individuals with a visual impairment up

27 front rather than trying to retrofit after the environment has been built. Specific design considerations were suggested. Blasch, B., Wiener, W. & Welsh, R. (Eds.) 1997. Foundations of Orientation and Mobility, Second Edition, New York: American Foundation for the Blind Press, Inc. This textbook is used in the training of Orientation and Mobility Specialists through out the US and other English speaking countries. It contains 24 Chapters including chapters on Orientation Aids and Environmental Accessibility. Crandall, W; Brabyn, J; Bentzen, BL; Myers, L. (1999). Remote Infrared Signage Evaluation for Transit Stations and Intersections. Journal of Rehabilitation Research and Development, Vol. 36. 4. This paper focuses on 2 problems that are among the most challenging and dangerous faced by blind travelers: negotiating complex transit stations and controlled intersections. The authors report on human factors studies of the Talking Signs remote infrared signage system in these critical tasks, examining such issues as how much training is needed to use the system, its impact on performance and safety, benefits for different population subgroups, and user opinions of its value. Results indicate that blind people can quickly and easily learn to use remote infrared signage effectively, and that its use improves travel safety, efficiency, and independence. Flemming, J. (1998) A Simple Act, Often Forgotten. Community Transportation. Community Transportation Association of America. Vol 16, Issue 4. Close to eight years have elapsed since the signing of the Americans with Disabilities Act (ADA). Before the celebration of the 10th anniversary, some members of the disability community are beginning to identify the areas where real progress has been made and those where substantial work remains. FTA reports that 68% of the approximately 50,000 fixed route buses are lift equipped today, a far cry from 1990. However, the act of putting a lift on a bus does not by itself make that bus accessible. The information in this article is based on information provided by the American Council of the Blind (ACB) - a national advocacy organization for people with visual disabilities - which has assumed a proactive role in making fixed route public transit services fully accessible to the blind community. ACB's efforts have been directed at overcoming an important barrier experienced by blind and visually impaired persons in using fixed route bus and many rail services - compliance with the ADA mandate of calling out stops and making other related announcements. Announcing stops, routes and destinations is the accessibility equivalent to people with visual disabilities and those who cannot read of the lift for people with mobility impairments. Glick, PB., (1998). The ADA and Technological Solutions for Achieving Effective Communication With Hard of Hearing and Deaf People. Journal of Urban Technology. Vol 5, Issue 1. This article examines the various technologies being employed to enhance communication for hearing impaired people. Crowded and noisy sites are characteristic of urban life, and the barriers these pose to communication for citizens who are deaf or hard of hearing (DHH) can be partly overcome by technology. The public address systems in most theaters, concert halls, movie houses, exhibition spaces, lecture halls, and conference rooms are not effective in communicating speech to people who are DHH. The author discusses various technological approaches to overcoming communication barriers in public meeting places as part of her description of the comprehensive efforts being made by cities in the U.S. to comply with the accessibility standards for the deaf and hard of hearing.

28 Goto, K; Matsubara, H; Myojo, S. (1998). A New Passenger Guide System for Visually Disabled Persons. Railway Technical Research Inst, Quarterly Reports, Railway Technical Research Institute, Vol 39, Issue 4. This paper presents a new passenger guide system for visually disabled persons. The system uses the latest technologies such as data carriers, mobile communication and portable computers. Data carriers are embedded at many places in the station such as floors, platforms, and walls. Coded data recorded in data-carriers are transferred to users via a reader installed in the cane of the user. The data are interpreted by a portable computer, which generates appropriate guide messages utilizing geographical information and user's personal data stored in it beforehand. Guide messages are finally conveyed orally to the user via a portable speaker. Grubb, D. (2000). Pedestrian Safety Handbook: A Handbook for Advocates Dedicated to Improving the Pedestrian Environment Guaranteeing People Who Are Blind or Visually Impaired Access to Intersection Identification and Traffic Control Information. Second Edition. The American Council of the Blind Pedestrians, especially blind pedestrians, are at risk of injury or death every time they attempt to cross a street. Major impediments are multiple street intersections with complex pedestrian island configurations; traffic patterns controlled by underground sensors that change the signaling at intersections to accommodate heavier traffic flow resulting in a lack of predictability of the time available to cross the street; traffic circles without traffic signals; turning signal arrows that allow vehicles to cross in front or in back of moving pedestrians; signaling devices that are difficult to locate and understand; and blended or level curbs that are not always detectable at the entrance to the street. This handbook provides information for blind pedestrians in order to help them navigate through, and advocate for, safer streets. Hughes, RG; Turner, S; Landphair, H, (2002). On The Integrated Application of Modeling, Simulation, and 3d/4d Visualization: The Concept of a 'Laboratory' For Non-Motorized Travel Research. 9th World Congress on Intelligent Transport Systems. ITS America. The UNC Highway Safety Research Center (HSRC) and the Texas Transportation Institute (TTI) are jointly pursuing the development of a 'laboratory' capability for the integrated application of modeling, simulation, and visualization technologies to non-motorized (ped/bike) research. The simulator component is to be developed in conjunction with the existing TTI driving simulator built by Hyperion/KQ Corporation (now Global Sim) and housed on the Texas A&M campus. HSRC is currently using the VISSIM model in a stand-alone (i.e., non-integrated) mode on NIH-sponsored research addressing the problems of blind and visually impaired pedestrians at complex intersections (e.g., roundabouts). An expansion of the NIH work is anticipated that will permit the integrated application of modeling and simulation over the next year. The work with NIH will also permit exploration of the possibility of a high fidelity 'aural' simulation of the operational traffic environment (important to the blindness community). Such a simulation would be possible with the integration of the real time traffic modeling capabilities of VISSIM (or other similar model) and auditory psychophysics capabilities of the Vanderbilt partner of the NIH bioengineering research partnership (BRP). Such an application would also present new opportunities for the system development and evaluation of 'accessible pedestrian signal' (APS) concepts. A major goal is to be able to fully integrate the constructive simulation capabilities of a model such as VISSIM with the real time multi-modal capability of the TTI driving simulator. The ability to integrate real time and constructive simulation capabilities (and in turn the derivative capabilities for 3D/4D visualization) will represent a major step toward being able to utilize these technologies to convincingly demonstrate the 'operational' benefits of advanced Intelligent Transportation System (ITS) concepts prior to their actual implementation. It will have the effect of being able to move beyond the use of 3D/4D

29 visualization technologies to simply show how advanced system concepts will 'look' to where we will be able to demonstrate (with the confidence of underlying micro-simulation models) how they will 'operate' as well. Being able to provide an operationally realistic (traffic) environment in the simulator will significantly increase the utility of the simulator as a research tool for the analysis of driver, vehicle, and system variables involved in advanced transportation system concepts. Hunter-Zaworski, K; Hron, ML. (1999). Bus Accessibility for People With Sensory Disabilities. Transportation Research Record. Issue 1671. With the passage of the Americans with Disabilities Act (ADA) it has become a civil rights violation to deny access to public transportation to people with disabilities. ADA requires transit agencies to provide accessible buses or equivalent services to people with mobility, sensory, or cognitive impairments. Issues concerning people with sensory impairments, and their access to fixed-route transit services, are examined in this study. The literature concerning access to public transit by people with sensory disabilities is summarized in this paper, along with exemplary training programs and technologies that have improved transit accessibility for people with sensory disabilities. A major conclusion of this study is that technological solutions may not increase bus accessibility for people with sensory impairments. One-on-one interaction is needed to solve many individual access problems of the transit users. Training for transit personnel is needed so personnel become aware of, and more sensitive to, the needs of all transit users. Training for the transit user is necessary so that use of the transit system is accomplished with grace, speed, efficiency, and dignity. Training for those who train people with disabilities is necessary so that transit travelers will be informed about all the available services offered by transit agencies. Visual signage must be consistent and highly legible to be effective and includes sign and information location, lighting, contrast, and content. Kelleher, DG (2002) Wayfinding Devices Designed and Installed For the Visually Impaired Community. Bus and Paratransit Conference, Proceedings American Public Transportation Association The Americans with Disabilities Act (ADA) has successfully addressed many of the needs of disabled people who had restricted mobility, and new technology becomes available every day to make things easier for the disabled community. This paper focuses on the use of The Talking Sign System, a wayfinding device that can reduce the barriers that blind and visually impaired people encounter when they are out in a built environment dominated by people who can see. Kuemmel, DA (2000). Accessible Pedestrian Signals. Institute of Transportation Engineers. Vol. 70,3 Over the past 20 years, the Signals Technical Committee of the National Committee on Uniform Traffic Control Devices has discussed the topic of audible pedestrian signals and always failed to reach a consensus on the addition of any language in the Manual on Uniform Traffic Control Devices regarding this. The Americans with Disabilities Act requires access to public right-of-way for people with disabilities. In 1997, the issue was given to the Pedestrian Task Force to explore and provide recommendations on proposed language on a much broader issue than just audible pedestrian signals. The Traffic Engineering Council Accessible Intersection Committee is working to develop tools that will help traffic engineers make intersections more accessible for the blind and visually impaired. Proposed standards for accessible pedestrian signals are included. La Grow, S., and Blasch, B. (1992). Orientation and Mobility for Older Adults with Impaired Vision. In Alberta Orr (Ed) Aging and Vision Loss in the United States. New York: American Foundation for the Blind, Inc.

30 This Chapter deals with the unique travel considerations for the mobility of older adults with impaired vision. Included are some of the common functional mobility limitations experienced by the older adult with impaired vision and some suggested solutions. Loane, Gregg; Greenough, John C., (1998). Audible Pedestrian Signals in the City of Toronto: A Municipal and Corporate Partnership with the Blind and Visually Impaired Communities. 68th Annual Meeting of the Institute of Transportation Engineers. Institute of Transportation Engineers. The use of Audible Pedestrian Signals (APS) is not new to North America. APS have been in operation from coast to coast, in one form or another, for decades. While a newcomer to this technology, the City of Toronto Transportation Department (Toronto Transportation) has developed a means of community consultation that may be of benefit to other municipalities in their attempts to provide for the best possible APS program. This paper describes how APS operate in the City of Toronto, functions of the APS Advisory Group, and reactions to the APS program. Marin-Lamellet, C; Pachiaudi, G; Le Breton-Gadegbeku, B, (2001). Information And Orientation Needs of Blind And Partially Sighted People in Public Transportation: Biovam Project. Transportation Research Record, 1779 Presented are results of the BIOVAM project in France concerning the problems experienced by the visually impaired who use public transportation, such as buses, subways, and trains. The project focused on information gathering and orientation processes in the public transportation context. The BIOVAM approach uses a questionnaire survey to identify the main difficulties that public transportation users with visual impairment must manage. The approach includes a review of promising devices that could reduce these difficulties, such as personal information systems and tactile pavements. An overview of the results obtained from the survey is presented, addressing the use of buses and subways. The main technical solutions considered by the project are described, and the research protocols that are to be used in the field experiments are presented. The results of the BIOVAM project could be used to make concrete recommendations to include the specific needs of travelers with visual impairment in the design of a public transport infrastructure. Norio N, (2002). Development of a Traffic Signal System to Improve Mobility of The Visually Impaired. 9th World Congress on Intelligent Transport Systems, ITS America. Recently, safe walking by the visually impaired has become a socially important issue. It is especially dangerous when a totally blind person crosses an intersection, so some safety measures must be taken. Installation of an audible signal is fundamentally a top priority and it's desirable to increase the amount of information with an additional device. Some trial equipment was made with consideration for the advice from the users, with which verification tests were made. The paper discusses how the trial equipment could easily be used in the field after some modifications. About 3 million Japanese struggle with disabilities, 300,000 of which are visually impaired, as reported by the Ministry. In 1990 "the Barrier-free Law" was established by the related Ministry, with which much planning is being promoted in various circles to assist the handicapped in supporting themselves and participating freely in society. This project, which aims to enhance the mobility of the visually impaired, conducted a study on measures to eliminate difficulties associated with crossing intersections. One of the main problems is that there is no uniformity between audible signals at intersections among the different prefectures. With consideration for user-friendliness, safety and amenity, a new system of audible signals, which enable navigational guidance to the handicapped with uniformed sounds in Japan needs to be developed.

31 Ross, David & Blasch, B., (2002) Development and Evaluation of three Way-Finding Interfaces for People with Severe visual Impairment. IEEE Transactions on Rehabilitation Engineering. This research study compared three methods of providing an individual with a visual impairment feedback to make a straight street crossing. The methods included a speech interface, a virtual 3D Sonic beacon and a “tapping” tactile interface. Based on the data, the recommended interface was the tapping tactile interface. It was noted that the speech and 3D beacon had some limitations due to the traffic sounds masking the feedback and also several of the subjects had hearing losses. Williams, M. & Blasch, B. (2003) “Field Comparison of Accessible Pedestrian Devices,” International Mobility Conference (IMC), Stellenbosch, South Africa. April 5, 2003. This study compared two Accessible Pedestrian Signals (APS) to the existing pedestrian crossing signal. The research was conducted in two parts. Experiment 1 will provide a field replication of a study conducted by Van Houten, Blasch, and Malenfant that compared the relative conspicuity of the Relume™ signal by comparing three different symbols (hand, person, and animated eyes) for low vision individuals. Experiment 2 will compare the effectiveness of two accessible pedestrian signals compared to a typical pedestrian traffic light signal as a control. The Relume™ and Polaria signals will be installed at two intersections along the same street. The dependent variable, amount of veering (deviation veer and signed veer) will be measured at each crossing. Whether deviations are toward or away from the intersection (signed veer) will also be recorded with measures of crossing alignment. At the time of this presentation, all of the data had not been collected

32 ADDITIONAL REFERENCES INCLUDED IN TEXT Bentzen, B.L., Barlow, J.M. & Franck, L. (2000). Addressing Barriers to Blind Pedestrians at Signalized Intersections. ITE Journal, 70-9: 32-35. Washington, DC: Institute of Transportation Engineers. Bentzen, B.L., Crandall, W.F., Chigier, B., Warden, G.F. & Carosella, L. (1995). Comprehensive Wayfinding System for Transportation Services: Talking Signs® and Speak2Directions. Proceedings: Orientation and Navigation Systems for Blind Persons. University of Hertfordshire, Hatfield, England, Feb. 1-2, 1995. Bentzen, B.L., & Tabor, L.S. (1998). Accessible Pedestrian Signals. U.S. Access Board. Blasch, B. (1999). Effectiveness of Accessible Pedestrian Signals. Final Report, Developmental Research Project funded by the Atlanta, Veterans Affairs Medical Center, Rehabilitation Research and Development Center. Blasch, B., Wiener, W. & Welsh, R. (Eds.) 1997. Foundations of Orientation and Mobility, Second Edition, New York: American Foundation for the Blind Press, Inc. Clark, D.O. & Maddox, G.L. (1992). Racial and Social Correlates of Age-related Changes in Functioning. Journal of Gerontology, 47, 5, S222-S232. Crandall, W., Brabyn, J., Bentzen, B.L., & Myers, L. (1998). Remote Infrared Signage Evaluation for Transit Stations and Intersections. Journal of Rehabilitation Research and Development, 36. Crandall, W.F., Bentzen, B.L., Myers, L. & Mitchell, P.A. (1995). Transit Accessibility Improvement Through Talking Signs® Remote Infrared Signage: Administration and Evaluation. Final report. US Department of Transportation, Federal Transit Administration and Project ACTION of the National Easter Seal Society. Crews, John E. (1991). Measuring Rehabilitation Outcomes and the Public Policies of Aging and Blindness.” In Vision and Aging: Issues on Social Work Practice. (Ed. Nancy D. Weber), New York: Hawthorne. De l’Aune, William. 2002. “Population Estimates of Legally Blind and Visually Impaired Veterans 2002- 2012.” Report to CARES Resource Allocation Conference: Washington, D.C. De l’Aune, W., Williams, M., & Welsh, R. (1999). Development of Valid and Reliable Outcome Measures of the VA Blind Rehabilitation Programs. Journal of Rehabilitation Research and Development, 36-4, 273-293. Department of Transport (1993). The Use of PUFFIN Pedestrian Crossings. London Department of Transport, Network Management and Driver Information Division. London, England. Goodrich, Gregory. 1995. “Growth in a Shrinking Population: Visual Impairment in the Veteran Population 1995-2010.” Internal Report, Department of Veterans Affairs: Washington, DC. Green, D.M., and Swets, J.A. (1966) “Signal detection theory and psychophysics”, Wiley & Sons, New York. Haegersrtrom-Portnoy, Gunilla, Madelyn Schneck and John Brabyn. 1999. “Seeing into Old Age: Vision Function Beyond Acuity.” Optometry and Vision Science, 76(3): 141-158.

33 Hall, G., Rabelle, A. & Zibihaylo, C. (1994). Audible traffic signals: A new definition. Montreal: Montreal Association for the Blind. Hulscher, F.R. (1976). Traffic Signal Facilities for Blind Pedestrians. Australian Road Research Board Proceedings, Z 8, 13-26. Jacobson, W.H. (1993). The Art and Science of Teaching Orientation and Mobility to Persons with Visual Impairments. New York: AFB Press. Kovar M, Lawton M. (1994). Functional Disability: Activities and Instrumental Activities of Daily Living. In M. Lawton and Teresi J. (Eds.) Focus on Assessment Techniques. Annual Review of Gerontology and Geriatrics, 14:57-75. LaGrow, S. & Weessies, M. (1994). Orientation and mobility: Techniques for independence. Palmerston North, New Zealand: Dunsmore. Manton, Kenneth G., Corder, Larry S., & Stallard, Eric. (1993). Estimates of Change in Chronic Disability and Institutional Incidence and Prevalence Rates in the U.S. Elderly Population form the 1982, 1984, and 1989 National Long Term Care Survey. Journal of Gerontology, 48, S153-166. National Eye Institute (NEI). 2001. Vision Research: A National Plan 1999-2003. Office of Science Policy and Legislation, National Eye Institute, National Institutes for Health. Bethesda, MD: Government Printing Office. Oliver, M. (1989). Audible Pedestrian Signals: A Feasibility Study. Virginia: Masters thesis. Patterson, R. D. (1982). “Guidelines for auditory warning systems on civil aircraft,” Civil Aviation Authority, Paper 82-017, London. Peck, A. & Uslan, M. (1990). The Use of Audible Traffic Signals in the US. Journal of Visual Impairment and Blindness, 84, 547-551. Pope, Andrew M. & Tarlov, Alvin R. (1991). Disability in America: Toward a National Agenda for Prevention. Washington, DC: National Academy Press. Siques, J. Effects of Pedestrian Treatments on Risky Pedestrian Behavior. Transportation Research Record No.1793. Paper No. 02-2887. Transportation Research Board, 2002. Siques, J. Pedestrian Warning and Control Devices, Guidelines and Case Studies. Transportation Research Record No. 1762. Paper No. 01-2513. Transportation Research Board, 2001. Skeiber, S.C., Mason, R.L., and Potter, R.C. (1977) “Effectiveness of audible devices on emergency vehicles, U.S. Department of Transportation, National Highway Traffic Safety Administration, DOT-TSC-OST-77-38. Sorkin, R. D., “Design of Auditory and Tactile Displays,” in Handbook of Human Factors, edited by G. Salvendy (John Wiley and Sons, Inc., New York, 1987), pp. 449-576. Swets, J.A., and Green, D.M., (1975) “A proposed standard fire-alarm signal”, J. Acoust. Soc. Am., Vol. 57, No. 3, 756-757. Stevens, A. (1993). A Comparison Study of the Ability of Totally Blind Adults to Align and Cross the Street at an Offset Intersection Using an Alternating versus a Non-alternating Audible Traffic Signal. Sherbrooke: Masters thesis.

34 U.S. Department of Commerce, Bureau of the Census. 2001. Profiles of General Demographic Characteristics: 2000 Census of Population and Housing. Washington, D.C.: Economics and Statistics Administration. U.S. Department of Veterans Affairs. 1999. Blind Rehabilitation Gold Ribbon Panel Report. Washington, D.C.: Department of Veterans Affairs Blind Rehabilitation Service. Van Houten, Blasch, and Malenfant (2001) A Comparison of the Recognition Distance of Several Types of Pedestrian Signals with Low Vision Pedestrians. Under review by the Journal of Rehabilitation Research and Development Van Houten, Blasch, and Malenfant, JEL (2001) Use of Animated Eyes in Pedestrian Signals Increases WALK Sign Recognition Distance of Low Vision Pedestrians. Journal of Rehabilitation Research and Development, 38,443-448. Van Houten, R, Retting, R.A., Van Houten, J., Farmer, C.M. & Malenfant, J.E.L. (1999). The use of animation in LED pedestrian signals to improve pedestrian safety. ITE Journal, 69, 30-38. Van Houten, R., Malenfant, J., Van Houten, J. & Retting, R. (1997). Using Auditory Pedestrian Signals to Reduce Pedestrian and Vehicle Conflicts. Transportation Research Record No. 1578. Washington, DC: National Academy Press. Verbrugge LM, Gruber-Baldini AL, Fozard JL. (1996) Age differences and age changes in activities: Baltimore Longitudinal Study of Aging. Journal of Gerontology, 51: S30-41. Watson, Gale. 2001. “Low Vision in the Geriatric Population: Rehabilitation and Management.” Journal of the American Geriatrics Society, 49(3).