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Traffic Signal Control Strategies for Pedestrians and Bicyclists (2022)

Chapter: Chapter 10 - Techniques for Multistage Crossings

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Suggested Citation:"Chapter 10 - Techniques for Multistage Crossings." National Academies of Sciences, Engineering, and Medicine. 2022. Traffic Signal Control Strategies for Pedestrians and Bicyclists. Washington, DC: The National Academies Press. doi: 10.17226/26491.
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Suggested Citation:"Chapter 10 - Techniques for Multistage Crossings." National Academies of Sciences, Engineering, and Medicine. 2022. Traffic Signal Control Strategies for Pedestrians and Bicyclists. Washington, DC: The National Academies Press. doi: 10.17226/26491.
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Suggested Citation:"Chapter 10 - Techniques for Multistage Crossings." National Academies of Sciences, Engineering, and Medicine. 2022. Traffic Signal Control Strategies for Pedestrians and Bicyclists. Washington, DC: The National Academies Press. doi: 10.17226/26491.
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Suggested Citation:"Chapter 10 - Techniques for Multistage Crossings." National Academies of Sciences, Engineering, and Medicine. 2022. Traffic Signal Control Strategies for Pedestrians and Bicyclists. Washington, DC: The National Academies Press. doi: 10.17226/26491.
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Suggested Citation:"Chapter 10 - Techniques for Multistage Crossings." National Academies of Sciences, Engineering, and Medicine. 2022. Traffic Signal Control Strategies for Pedestrians and Bicyclists. Washington, DC: The National Academies Press. doi: 10.17226/26491.
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Suggested Citation:"Chapter 10 - Techniques for Multistage Crossings." National Academies of Sciences, Engineering, and Medicine. 2022. Traffic Signal Control Strategies for Pedestrians and Bicyclists. Washington, DC: The National Academies Press. doi: 10.17226/26491.
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Suggested Citation:"Chapter 10 - Techniques for Multistage Crossings." National Academies of Sciences, Engineering, and Medicine. 2022. Traffic Signal Control Strategies for Pedestrians and Bicyclists. Washington, DC: The National Academies Press. doi: 10.17226/26491.
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Suggested Citation:"Chapter 10 - Techniques for Multistage Crossings." National Academies of Sciences, Engineering, and Medicine. 2022. Traffic Signal Control Strategies for Pedestrians and Bicyclists. Washington, DC: The National Academies Press. doi: 10.17226/26491.
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Suggested Citation:"Chapter 10 - Techniques for Multistage Crossings." National Academies of Sciences, Engineering, and Medicine. 2022. Traffic Signal Control Strategies for Pedestrians and Bicyclists. Washington, DC: The National Academies Press. doi: 10.17226/26491.
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Suggested Citation:"Chapter 10 - Techniques for Multistage Crossings." National Academies of Sciences, Engineering, and Medicine. 2022. Traffic Signal Control Strategies for Pedestrians and Bicyclists. Washington, DC: The National Academies Press. doi: 10.17226/26491.
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Suggested Citation:"Chapter 10 - Techniques for Multistage Crossings." National Academies of Sciences, Engineering, and Medicine. 2022. Traffic Signal Control Strategies for Pedestrians and Bicyclists. Washington, DC: The National Academies Press. doi: 10.17226/26491.
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Suggested Citation:"Chapter 10 - Techniques for Multistage Crossings." National Academies of Sciences, Engineering, and Medicine. 2022. Traffic Signal Control Strategies for Pedestrians and Bicyclists. Washington, DC: The National Academies Press. doi: 10.17226/26491.
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Suggested Citation:"Chapter 10 - Techniques for Multistage Crossings." National Academies of Sciences, Engineering, and Medicine. 2022. Traffic Signal Control Strategies for Pedestrians and Bicyclists. Washington, DC: The National Academies Press. doi: 10.17226/26491.
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Suggested Citation:"Chapter 10 - Techniques for Multistage Crossings." National Academies of Sciences, Engineering, and Medicine. 2022. Traffic Signal Control Strategies for Pedestrians and Bicyclists. Washington, DC: The National Academies Press. doi: 10.17226/26491.
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Suggested Citation:"Chapter 10 - Techniques for Multistage Crossings." National Academies of Sciences, Engineering, and Medicine. 2022. Traffic Signal Control Strategies for Pedestrians and Bicyclists. Washington, DC: The National Academies Press. doi: 10.17226/26491.
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Suggested Citation:"Chapter 10 - Techniques for Multistage Crossings." National Academies of Sciences, Engineering, and Medicine. 2022. Traffic Signal Control Strategies for Pedestrians and Bicyclists. Washington, DC: The National Academies Press. doi: 10.17226/26491.
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Suggested Citation:"Chapter 10 - Techniques for Multistage Crossings." National Academies of Sciences, Engineering, and Medicine. 2022. Traffic Signal Control Strategies for Pedestrians and Bicyclists. Washington, DC: The National Academies Press. doi: 10.17226/26491.
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160 This chapter describes treatments that might be applied in connection with multistage cross- ings and have not been described in previous chapters: C H A P T E R 1 0 Techniques for Multistage Crossings Primary Function Section Treatment Name Provide convenient and accessible crossings 10.1 Multistage Crossings Reduce pedestrian delay using left-turn overlaps 10.2 Left-Turn Overlap for Pedestrian Half- Crossings Provide safe crossings for bicycles at multistage crossings 10.3 Single-Pass Bicycle Crossings with Two-Stage Pedestrian Crossings Multistage Crossings (Section 10.1) addresses general themes related to pedestrian cross- ings, including pedestrian signalization options, accessibility considerations, and the critical importance of pedestrian progression in mitigating pedestrian delay at multistage crossings. Left-Turn Overlap for Pedestrian Half-Crossings (Section 10.2) explains a technique that creates more opportunities for pedestrians to cross to or from a median island by letting them cross during left-turn phases, thereby reducing their delay. The potential to use this treatment depends heavily on whether left-turn phases are actuated versus on recall (see Section 7.5) and whether minimum green is adapted to demand (part of Section 7.3, which discusses maximizing Walk interval length). Single-Pass Bicycle Crossings with Two-Stage Pedestrian Crossings (Section 10.3) is a treatment that acknowledges speed differences between bicycles and pedestrians, as well as their differing storage area requirements, and describes how this can lead to serving them differently at intersections with multistage crossings. Pertinent Treatments Described in Previous Sections In Chapter 6, Channelized Right Turns/Delta Islands (Section 6.4) describes a treatment that creates signalized multistage crossings if the crossings between the sidewalk and delta islands are signalized. Several techniques described in earlier sections can play an important role in improving multistage crossings: • Pedestrian Overlaps with Leading Pedestrian Intervals and Vehicular Holds (Section 6.7). • Short Cycle Length (Section 7.1). Because virtually all pedestrian crossings are two-way, providing good progression in both directions is only possible when a cycle is short. At the same time, using multistage crossings can sometimes make it possible to have a shorter cycle.

Techniques for Multistage Crossings 161   • Reservice (Section 7.2). is treatment is especially relevant in relation to partial crossings to and from delta islands. • Maximizing Walk Interval Length (Section 7.3). • Pedestrian Recall versus Actuation (Section 7.5). is treatment is especially pertinent in relation to le-turn overlaps. In addition, measuring pedestrian delay (see Section 3.3) is particularly critical with multi- stage crossings. e rule that pedestrian delay is roughly proportional to cycle length does not apply with multistage crossings. Pedestrian delay can be far greater than one might expect unless a timing plan ensures good progression. With multistage crossings, it is important to measure pedestrian delay by direction because the delay to pedestrians walking in one direction through a set of partial crossings can be substantially dierent from the delay to those walking through the same set of partial crossings but in the opposite direction. 10.1 Multistage Crossings 10.1.1 Basic Description 10.1.1.1 Alternative Names None. 10.1.1.2 Description and Objective A multistage crossing is a crossing that is physically divided into two or more partial crossings interrupted by crossing islands, also called refuge islands (see Exhibit 10-1). By breaking a long crossing into parts, multistage crossings can improve pedestrian safety and comfort as well as make crossings more accessible to pedestrians with walking disabilities. Multi- stage crossings can improve intersection eciency due to the shorter pedestrian clearance interval requirements, which may lead to shorter signal cycles and greater capacity. In addition, multistage crossings can reduce pedestrian delay if more crossing opportunities and signal progression from Source: Google Maps. Exhibit 10-1. Multistage crossing example at the intersection of East Flamingo Road and Boulder Highway in Las Vegas, NV.

162 Traffic Signal Control Strategies for Pedestrians and Bicyclists one partial crossing to the next are given to pedestrians. An example of this is overlapping pedes- trian phases with left-turn phases that are not in conflict with one another (see Section 10.2). At the same time, multistage crossings can lead to exceedingly long pedestrian and bicycle delays if signal timing does not provide good progression between partial crossings. With poor progression, average pedestrian delay for multistage crossings can be more than double the delay of a single-stage crossing. Pedestrian noncompliance is known to increase with delay, posing a significant safety issue if signal timing causes long waiting times on a crossing island. Furthermore, pedestrians often complain about signal timing that leaves them stranded in the middle of the street. Therefore, a critical objective in the design of multistage crossings, not just for convenience but for safety as well, is to minimize pedestrian delay by providing progression from one partial crossing to the next. 10.1.1.3 Variations Where an island physically divides a crossing into two parts, different configurations can be used that determine the degree to which the crossing functions as a multistage versus single- stage crossing: a. Treat it as a simple, single-stage crossing with no waiting intended in the island. Passage through the island is treated as part of the crosswalk, and the pedestrian clearance interval is based on crossing the full street. Formally, this is not a multistage crossing, and no signals or detection is provided on the island. The crossing island may be used informally. This treat- ment is used, for example, in Cambridge, MA, on the northern part of Massachusetts Avenue. b. Design the island as a pedestrian refuge, but time signals so that nobody has to wait at the island. The island includes pedestrian displays facing both directions, accessible pushbuttons for both directions, and truncated domes. However, the pedestrian phases are timed assum- ing that there is no island, with the pedestrian clearance time calculated for crossing the entire street. This typically results in a short Walk interval and a long Flashing Don’t Walk (FDW) interval. With this configuration, no pedestrian who begins crossing during the Walk interval will have to wait on the island, except for very slow pedestrians. This option presents some ambiguity because pedestrians are expected to leave the median island facing a FDW display, a sign that normally means “don’t begin crossing.” New York City uses this option for cross- ings of Broadway north of 59th Street. c. Design the island as a pedestrian refuge and provide a pedestrian phase long enough for a single-stage crossing, but run the pedestrian signals for half-crossings. As in Option b, the island is designed as a pedestrian refuge, but in this configuration, the pedestrian clearance intervals are based on the lengths of the half-crossings and are therefore relatively short. To support a single-stage crossing, the Walk interval is long. Pedestrians who begin crossing early in the Walk interval can cross in a single stage, while those who begin later in the Walk interval will only have enough time to reach the island and will have to wait there until the next cycle. This option has less pedestrian delay than Option b since those who begin late in the Walk interval will finish their crossing sooner than if they had waited until the next cycle to start crossing (as they would in Option b). New York City uses this option for crossings of Queens Boulevard. d. Design the island as a pedestrian refuge, time pedestrian signals for half-crossings, and do not provide a single-stage crossing. This is the general case for a multistage crossing, offering the greatest flexibility. However, it also carries the danger that unless signal timing ensures good progression for pedestrians between each crossing, pedestrian delay could be very high. At intersections with channelized right turns and delta islands (see Section 6.4), crossings across the channelized turns are considered stages of a crossing if they are signalized. It is possible to have a crossing that is two-stage for pedestrians yet single-stage for bicycles, as discussed in Section 10.3.

Techniques for Multistage Crossings 163   An intersection where pedestrians have a strong desire line for a diagonal crossing but have to make it by following two square crossings can be considered a two-stage pedestrian crossing. Techniques for multistage crossings can therefore be applied to serve such desire lines, just as they are applied to two-stage left turns for bicycles (see Section 9.3), which can also be consid- ered a type of multistage crossing. 10.1.1.4 Operating Context Multistage crossings might be appropriate for intersections: • With long crossings where providing a single-stage crossing can drastically impact inter- section capacity; • With a crossing that has an existing median large enough to serve as a safe waiting area for pedestrians; • Where there are channelized right turns and either intersection geometry or a high volume of right-turn traffic makes it unsafe to allow unsignalized partial crossings across the right-turn lane (see Section 6.4); and • Where pedestrians or bicyclists have an important diagonal desire line that is served by a pair of square crossings. At the same time, unless signal timing can offer good progression from one partial crossing to the next, it may be more appropriate to avoid multistage crossings or to time the pedestrian signals for single-stage crossings. 10.1.2 Applications and Expected Outcomes 10.1.2.1 National and International Use Multistage crossings are a standard treatment both in the United States and internationally. They are more common in countries where multilane roads usually have medians (because long, uninterrupted pedestrian crossings are discouraged), such as the Netherlands. A key difference between Dutch and American practice is that in the Netherlands, minimizing pedestrian delay is an essential part of multistage crossing design, while in typical American practice, pedestrian delay at multistage crossings is rarely measured or minimized. As a result, average pedestrian delay often ends up being extremely long—sometimes exceeding 120  s, which is more than double the 60 s threshold at which pedestrian level of service is “F” (Highway Capacity Manual, 2000). To avoid these long delays and associated safety problems, some U.S. cities seek to avoid multi stage crossings or at least time signals to facilitate single-stage crossings. For example, before 2000 many NYC crossings of wide streets with medians were timed for two-stage cross- ings, but they have all since been retimed so that pedestrians can cross in a single stage. 10.1.2.2 Benefits and Impacts Benefits and impacts discussed in this section include: • Safety and accessibility benefits of interrupting a long crossing with a pedestrian island; • Safety and delay benefits from replacing multistage crossings with single-stage crossings; • Delay reductions as a result of improved pedestrian progression; and • Delay reductions and safety improvements gained by facilitating short signal cycles. Measuring delay impacts requires a method to measure pedestrian delay at multistage cross- ings. The Northeastern University Ped and Bike Crossing Delay Calculator is a free tool that can be used for this purpose, available at https://peterfurth.sites.northeastern.edu/2014/08/02/ delaycalculator/ (Furth et al., 2019). A new Highway Capacity Manual (HCM) procedure and

164 Traffic Signal Control Strategies for Pedestrians and Bicyclists computational engine for measuring pedestrian delay at multistage crossings has also been developed (Ryus et al., in press), which will be included in an update of the HCM that was in publication at the time of writing. Safety and accessibility benefits of interrupting a long crossing with a pedestrian island. A long crossing can be a barrier to slower pedestrians. Interrupting it with a refuge island can enable pedestrians with disabilities to cross a street that they might not otherwise be able to cross. Similarly, long crossings present a hazard to pedestrians who, for any reason, find them- selves only partway across the street when the signal is about to change (e.g., adults crossing with small children). A refuge island shortens the crossing distance and improves safety. Safety and delay benefits from replacing multistage crossings with single-stage crossings. Queens Boulevard is a wide road in New York City, including a six-lane central roadway with a wide median as well as a pair of service roads on the outside. Before 2002, almost all crossings along Queens Boulevard were timed such that pedestrians had to wait approximately 100 s in the median before they could finish their crossing, leading to poor compliance. In 2002, signals were retimed to provide a single-stage crossing, which required a crossing phase of 60 s and increased the cycle length from 120 to 150 s in peak periods. Average pedestrian delay was reduced from 144 s to 53 s. There were 10.0 pedestrian fatalities per year on average over the period 1993–1998, followed by 4.7 per year over the period 1999–2001 as various safety improvements were made. This number fell to 1.5 fatalities per year after a single-stage crossing was implemented (NYC DOT, 2007). In Brookline, MA, changes in the signal timing in 2007 required pedestrians crossing Beacon Street at Harvard Street to cross in two stages (Beacon Street has a wide median with light rail transit running in the middle). Pedestrian noncompliance was nearly 100% (i.e., scarcely any pedestrian stopped and waited in the middle). Pedestrians were often still in the crosswalk when Beacon Street’s green phase began, creating friction with motorists. In response to citizen com- plaints, the signal was retimed by shifting a few seconds from one phase to another so that pedes- trians could have a single-pass crossing. Noncompliance and friction with motorists at the start of the green largely disappeared. Impacts to motorists from the timing change were negligible. Delay reductions as a result of improved pedestrian progression. With poor progression, pedestrian delay at multistage crossings can be very long; with good progression, it can some- times be far smaller. Findings reported from various studies include: • A parkway intersection in Boston, MA, was recently reconfigured with a three-stage crossing whose average pedestrian delay was 123 s. Neither the designer nor the approving agencies knew what the average pedestrian delay was because it had never been calculated. A study found that with small adjustments to the timing plan, good progression could be provided for pedestrians crossing in both directions; average pedestrian delay was reduced to 41 s, and average vehicular delay increased by less than 1 s (Furth et al., 2019). One of the techniques used to create this good progression was a short vehicular-hold interval, in which all vehicular phases are held in red while pedestrian phases overlap (see Section 6.7). • A study found that pedestrian overlaps with left-turn phases (see Section 10.2) could be used to reduce average pedestrian delay at a two-stage crossing in Brookline from 86 s to 26 s, with only minor changes to vehicular signal timing (Furth et al., 2019). • Research done for this guidebook found that at an intersection in Evansville, IN, a shared-use path has a two-stage crossing involving a channelized right turn with an average bicycle delay of 66 s. Giving the channelized right turn its own phase and developing signal timing so the shared-use path crossing has good progression would reduce average bicycle delay for this crossing to 14 s. The only impact to traffic would be a small increase in delay to an affected right-turn movement.

Techniques for Multistage Crossings 165   Delay reductions and safety improvements gained by facilitating short signal cycles. At a midblock crossing with a wide median, replacing a single long crossing with a pair of short partial crossings can lead to a short cycle length. In such a case, timing the two half-crossings so that they are offset from each other by half a cycle can provide good progression for pedestrians walking in both directions. Furth et al. (2019) provides an example of a midblock crossing in a coordinated system with a single-stage crossing and a cycle length of 100 s. With a two-stage crossing, the cycle length could be only 50 s, reducing average pedestrian delay from 39 s to 30 s while reducing delay for autos as well. 10.1.3 Considerations 10.1.3.1 Accessibility Considerations While multistage crossings create opportunities to improve pedestrian comfort and reduce individual crossing segments, there are challenges to integrating accessibility features with this treatment, particularly related to guiding pedestrians to the appropriate refuge area. When cross- ings are designed and operated in multiple stages, each individual segment should be designed as a single crossing with supporting treatments to aid in the crossing. 10.1.3.2 Guidance Not applicable for this treatment. 10.1.3.3 Relationships to Relevant Treatments Treatments that might apply at multistage crossings are listed in the introduction to Chapter 10. 10.1.4 Implementation Support 10.1.4.1 Equipment Needs and Features Except for Option a, described at the start of this section, applying multistage crossings requires that crossing islands be equipped with pedestrian signals facing both directions and corresponding pushbuttons (if the crossing is actuated). Accessible signals are highly desirable. When the pedestrian phase is actuated, a call for one partial crossing can be programmed to automatically trigger a call for the next partial crossing, which allows pedestrians arriving at the island to be served on the next partial crossing with little or no delay. To implement this feature, each pushbutton must be wired to a different controller port so that the pedestrian’s direction of crossing can be determined. 10.1.4.2 Phasing and Timing Section 10.1.2.2 provides examples of phasing and timing for this treatment. 10.1.4.3 Signage and Striping Not applicable for this treatment. 10.1.4.4 Geometric Elements A pedestrian refuge island must be at least 6 ft deep, preferably 8 ft. To serve as a crossing island for bicycles, an island should be at least 10 ft deep. Islands must have a large enough queuing area for a signal cycle with high demand. Where pedestrian or bicycle demand has periodic surges, such as at schools or entertainment venues, pedestrian volumes per hour are misleading; counts are needed by signal cycle, and elements should be sized for a high-demand cycle.

166 Trafc Signal Control Strategies for Pedestrians and Bicyclists When multistage crossings are used, the signal timing can create a situation where the second- stage crossing receives a Walk indication prior to the rst-stage crossing. To avoid having pedes- trians who are waiting for the rst-stage crossing mistakenly think they can start their crossing when the second-stage Walk is displayed, it is important to consider the placement of the two sets of pedestrian signal heads relative to the pedestrians’ line of sight. Additional guidance is provided in the section on le-turn overlap for pedestrian half-crossings (see Section 10.2). Bibliography Furth, P. G., Wang, Y. D., & Santos, M. A. (2019). Multi-Stage Pedestrian Crossings and Two-Stage Bicycle Turns: Delay Estimation and Signal Timing Techniques for Limiting Pedestrian and Bicycle Delay. Journal of Transportation Technologies, 9(04), 489. Highway Capacity Manual. (2000). TRB, National Research Council, Washington, DC. NYC DOT. (2007). Safe Streets NYC. http://www.nyc.gov/html/dot/downloads/pdf/safetyrpt07_4.pdf Ryus, P., Musunuru, A., Bonneson, J., Kothuri, S., Monsere, C., McNeil, N., LaJeunesse, S., Nordback, K., Kumfer, W., & Currin, S. (in press). NCHRP Research Report 992: Guide to Pedestrian Analysis. Transporta- tion Research Board, Washington, DC. 10.2 Left-Turn Overlap for Pedestrian Half-Crossings 10.2.1 Basic Description 10.2.1.1 Alternative Names None. 10.2.1.2 Description and Objective Where a refuge island divides a crossing into half-crossings, some half-crossings can run con- currently with le-turn phases as well as with their concurrent through phases. For example, in Exhibit 10-2, Crosswalks A and D could run concurrently during a phase serving eastbound and westbound le turns. e objective of this treatment is to reduce pedestrian delay through a multi- stage crossing by enabling pedestrians to cross in a single stage or with improved progression. (a) Example intersection layout (b) Phasing plan with pedestrian overlaps with left turns Exhibit 10-2. Half-crossings and the left-turn movements with which they can overlap.

Techniques for Multistage Crossings 167   10.2.1.3 Variations Not applicable for this treatment. 10.2.1.4 Operating Context Pedestrian overlaps with left-turn phases might be appropriate anywhere with multistage crossings and exclusive left-turn phases. This treatment is especially applicable where pedes- trians need more time to make the full crossing than the duration of the concurrent vehicular phase and where left-turn phases are on recall. 10.2.2 Applications and Expected Outcomes 10.2.2.1 National and International Use Having a pedestrian half-crossing run during a left-turn phase is a routine traffic control strategy. This tactic is used commonly in the Netherlands; it is less common, but not unusual, in the U.S. Danish signal design guidance stresses the need to consider the placement and design of the pedestrian signal heads when multistage pedestrian crossings are used and the signal timing produces a situation where the second-stage crossing receives a Walk indication before the first- stage crossing (referred to in Danish guidance as “green behind red”). To avoid having pedes- trians who are waiting for the first-stage crossing mistakenly think they can start crossing when the second-stage Walk is displayed, Danish guidance recommends that the pedestrian heads be placed such that the closest pedestrian signal (i.e., on the refuge island) dominates a pedestrian’s sight line. For example, this can be done by placing the two signals in a line on the same side of the crosswalk so that they appear close to each other in a pedestrian’s field of view. Another method, often used in Copenhagen, is to use three-head pedestrian signals (two Don’t Walk over one Walk) for the first-stage crossing to reinforce which signal head a pedestrian should be watching and to provide redundancy in case one Don’t Walk signal is non-functioning (see Exhibit 10-3) (Danish Road Directorate, 2018a). 10.2.2.2 Benefits and Impacts Where there is a two-stage crossing and the length of the concurrent through vehicular phase is not enough for pedestrians to cross, pedestrians may have to wait a long time on the median island. Extending the pedestrian phase for some or all half-crossings by having them overlap with a left-turn phase reduces delay. These longer half-crossing phases often improve pedestrian progression, which can lead to dramatically shorter delay and sometimes enable pedestrians to cross without waiting in the median at all. As an example, Furth et al. (2019), in a simulation experiment of the form of intersection shown in Exhibit 10-2, found that adding left-turn over- laps reduced average pedestrian delay from 86 s to 26 s. For intersections that are coordinated, left-turn overlaps may force left-turn phases to run to their maximum green more often instead of terminating early, which would reduce delay slightly for left turns and increase it slightly for the coordinated movements. Where left-turn demand is such that left-turn phases are never skipped and usually run to their maximum green, the impact on traffic will be negligible. If pedestrian phases are actuated, impacts to vehicular traffic will occur only in cycles with pedestrian calls. The same study by Furth et al. (2019) showed that adding left-turn overlaps to reduce pedestrian delay only increased intersection vehicle delay by 1 s at the intersection studied.

168 Trafc Signal Control Strategies for Pedestrians and Bicyclists 10.2.3 Considerations 10.2.3.1 Accessibility Considerations Not applicable for this treatment. 10.2.3.2 Guidance Not applicable for this treatment. 10.2.3.3 Relationships to Relevant Treatments Where le-turn and cross-street phases are actuated, maximizing the Walk interval length (see Section 7.3) is important for getting the best service for pedestrians. 10.2.3.4 Other Considerations See Section 10.1 for general considerations regarding multistage crossings. 10.2.4 Implementation Support 10.2.4.1 Equipment Needs and Features All modern controllers can support serving pedestrian phases during a le-turn overlap. Where le-turn and cross-street phases are actuated, special programming may be needed to ensure that Walk intervals take advantage of the full vehicular intervals. To illustrate using Exhibit 10-2, if the westbound le-turn phase runs longer than its minimum green due to le- turn demand, Crossing B—which overlaps with that le turn—should have a correspondingly longer Walk interval as well. is is not a built-in feature with many controllers, which typically Source: Danish Road Directorate (2018b). Exhibit 10-3. Examples of two- and three-head Danish pedestrian signals.

Techniques for Multistage Crossings 169   can only be set to give the Walk interval a xed length; however, with most controller soware, the desired outcome can be achieved with custom programming. 10.2.4.2 Phasing and Timing Dierent phasing sequences—leading les, laggings les, and a combination of the two— have dierent progression implications for pedestrian crossings that use le-turn overlaps. Exhibit 10-4 shows a phasing plan with leading le turns that might apply to the same inter- section layout discussed before and shown below. Crossings A and D overlap the east–west left-turn phase, which means that they extend through both the north–south phase and the le-turn phase that follows. e combined duration of the north–south phase and a le-turn phase is assumed to be enough to make a full north–south crossing. With this phasing sequence, northbound pedestrians can start Crossing B when the north– south phase begins and continue directly to Crossing A using the le-turn overlap to complete Source: Furth et al. (2019). Exhibit 10-4. Phasing plan with leading lefts, which provides ideal progression for Crossings B–A and C–D.

170 Trafc Signal Control Strategies for Pedestrians and Bicyclists the crossing; similarly, southbound pedestrians can do the same with Crossings C and D. How- ever, pedestrians making movements A–B and D–C cannot make a single-pass crossing; their route involves waiting at the median island. In summary, pedestrians get ideal progression only if they walk on the le side of the street. In the example cited earlier by Furth et al. (2019), pedes- trians were walking on the right side. (For reference, without le-turn overlaps, average delay on either side of the street would be 84 s.) An interesting question is whether it would be helpful to provide signs pointing out which side of the street oers better service. If le-turn phases are lagging instead, as in Exhibit 10-5, it can be observed that people walking on the right side of the street (Crossings A–B and D–C) get a single-pass crossing and better progression than people on the le side. Average delay for crossings A–B and D–C with lagging les is the same as the average delay for crossings B–A and C–D with leading les. And if one of the le-turn phases leads while the other lags, as in Exhibit 10-6 where the westbound le turn leads and the eastbound le turn lags, both southbound crossings (A–B and C–D) get ideal progression, while northbound crossings do not get desired progression. (If the le turns exchange position, northbound would be the favored direction.) However, with “lead- lag phasing” all four half-crossings—A, B, C, and D—overlap with a le turn, and the longer Walk intervals that result make this the least-delay option. In the example from Furth et al., lead-lag phasing results in the lowest average delay—14 s for pedestrians walking southbound and 38 s for those walking northbound, which averages to 26 s. 10.2.4.3 Signage and Striping Not applicable for this treatment. 10.2.4.4 Geometric Elements Section 10.2.2.1 provides an example of Danish guidance for pedestrian signal head placement and design for multistage crossings. Source: Furth et al. (2019). Exhibit 10-5. Phasing plan with lagging lefts, providing ideal progression for Crossings A–B and D–C.

Techniques for Multistage Crossings 171   Bibliography Danish Road Directorate. (2018a). Håndbog: Projektering af Trafiksignaler (Handbook: Traffic Signal Design). Copenhagen, Denmark. Danish Road Directorate. (2018b). Håndbog: Brug af Trafiksignaler (Handbook: Use of Traffic Signals). Copenhagen, Denmark. Furth, P. G., Wang, Y. D., & Santos, M. A. (2019). Multi-Stage Pedestrian Crossings and Two-Stage Bicycle Turns: Delay Estimation and Signal Timing Techniques for Limiting Pedestrian and Bicycle Delay. Journal of Transportation Technologies, 9(04), 489. 10.3 Single-Pass Bicycle Crossings with Two-Stage Pedestrian Crossings 10.3.1 Basic Description 10.3.1.1 Alternative Names None. 10.3.1.2 Description and Objective At intersections with two-stage crossings where a pedestrian refuge is not large enough to serve as a bicycle queuing area, signal timing can allow bicycles to cross a street in a single pass while pedestrians cross in two stages. For example, pedestrians may be given a Walk signal to advance to a crossing island while bicycles are held at the curb until the time at which they can cross without stopping at the island. One reason is that bicycles need less crossing time than pedestrians; another is that a pedestrian refuge island may not be large enough to serve as a bicycle queuing area. Source: Furth et al. (2019). Exhibit 10-6. Phasing plan with one left leading and one lagging, providing ideal progression and a wide crossing window for Crossings A–B and C–D.

172 Traffic Signal Control Strategies for Pedestrians and Bicyclists 10.3.1.3 Variations Not applicable for this treatment. 10.3.1.4 Operating Context This treatment is appropriate wherever pedestrians have a two-stage crossing and the crossing island is not large enough to serve as a bicycle queuing area. 10.3.2 Applications and Expected Outcomes 10.3.2.1 National and International Use In the Netherlands, it is not unusual for intersections to be timed for single-pass bicycle crossings while parallel pedestrians cross in two stages. Two examples in Delft are (a) crossing Wateringsevest at Noordeinde and (b) crossing Van Foreestweg at Prinses Beatrixlaan. Both examples use a left-turn overlap for pedestrian half-crossings (see Section 10.2) in which pedes- trians start crossing during a left-turn phase, advance to a median island, and wait there while bicycles are held at the curb during this phase. When the left-turn phase ends, pedestrians finish their crossing (their second stage), and bicycles are released to cross the full intersection in a single pass. In both cases, the median island is too small to serve as a bicycle queuing area. (In the second example, the median island is 13 ft, but the high volume of bicycles and mopeds on this route makes it too small to be a bicycle queuing area.) In the U.S., it is routine for bicycles to follow vehicle signals and make crossings in a single pass that pedestrians make in two stages. In principle, it can be possible to follow the same strategy when bicycles follow bike signals. 10.3.2.2 Benefits and Impacts Timing bicycle crossings separately from pedestrian crossings in this way allows bicycle and pedestrian phases to be tailored to the users’ different speeds, an intersection’s available queuing space, and phase overlap opportunities. Bicycle queues are kept off the island where they might otherwise overflow into the street, while pedestrian crossings—by taking advantage of phase overlap possibilities—constrain the signal cycle less than they would if they were single-stage, resulting in shorter cycles. In Boston, a study examined an intersection with a three-stage crossing whose crossing islands are too small for bicycle queuing, meaning bicyclists have to become pedestrians to cross. In addition, due to poor pedestrian progression, pedestrian delay is very long. Furth et al. (2019) found that a timing plan with a single-pass crossing for bicycles and a well-coordinated multistage crossing for pedestrians would reduce bicycle delay from 123 s to 42 s and reduce pedestrian delay from 123 s to 41 s, while increasing auto delay by less than 1 s and avoiding the need to enlarge the crossing islands to support bikes. 10.3.3 Considerations 10.3.3.1 Accessibility Considerations Not applicable for this treatment. 10.3.3.2 Guidance While both the Manual on Uniform Traffic Control Devices (MUTCD) (2009) and (Proposed) Public Rights-of-Way Accessibility Guidelines (U.S. Access Board, 2011) offer consistent guidance that 6 ft is the minimum depth (i.e., the dimension in line with pedestrian movement) for pedes- trian refuge islands, guidance is lacking regarding the minimum size for bicycle refuge islands.

Techniques for Multistage Crossings 173   Bicycles are about 6  long, but for a bicyclist to stop safely, the island depth should be longer in order to provide bicyclists with a short stopping zone and to provide a small oset between the bike and travel lanes. e AASHTO Guide for the Development of Bicycle Facilities (2012) rec- ommends a minimum depth of 10  in order to support bicycles with trailers. Further guidance is needed to address both the depth and breadth of bicycle queuing area required to account for bicycle demand and the need to support cargo bicycles, bicycles with trailers, three-wheelers, and other large bicycles. 10.3.3.3 Relationships to Relevant Treatments Not applicable for this treatment. 10.3.4 Implementation Support 10.3.4.1 Equipment Needs and Features Not applicable for this treatment. 10.3.4.2 Phasing and Timing Exhibit 10-7 shows an example intersection in which the bicycle crossing occurs in a single pass during Phase C, while the pedestrian crossing is divided into two stages, A and B. e pedestrian-crossing phases are coordinated to enable good progression walking east (A–B) as well as west (B–A). 10.3.4.3 Signage and Striping Not applicable for this treatment. N a. Layout b. Phasing Plan Exhibit 10-7. Intersection with a single-pass crossing for bicycles while pedestrians have a two-stage crossing: (a) layout and (b) phasing plan.

174 Traffic Signal Control Strategies for Pedestrians and Bicyclists 10.3.4.4 Geometric Elements To serve as a bicycle refuge, a crossing island should be deep enough for a bicycle to stop and still leave an offset to travel lanes (the AASHTO bike guide recommends that a crossing island be at least 10 ft deep). The island should also have a queuing area wide enough to hold the antici- pated demand per signal cycle. Bibliography American Association of State Highway and Transportation Officials. (2012). Guide for the Development of Bicycle Facilities, 4th Edition. Washington, DC. Furth, P. G., Wang, Y. D., & Santos, M. A. (2019). Multi-Stage Pedestrian Crossings and Two-Stage Bicycle Turns: Delay Estimation and Signal Timing Techniques for Limiting Pedestrian and Bicycle Delay. Journal of Transportation Technologies, 9(04), 489. Manual on Uniform Traffic Control Devices for Streets and Highways. (2009). FHWA, U.S. DOT. http://mutcd. fhwa.dot.gov/ U.S. Access Board. (2011). (Proposed) Public Rights-of-Way Accessibility Guidelines. Washington, DC.

Abbreviations and acronyms used without definitions in TRB publications: A4A Airlines for America AAAE American Association of Airport Executives AASHO American Association of State Highway Officials AASHTO American Association of State Highway and Transportation Officials ACI–NA Airports Council International–North America ACRP Airport Cooperative Research Program ADA Americans with Disabilities Act APTA American Public Transportation Association ASCE American Society of Civil Engineers ASME American Society of Mechanical Engineers ASTM American Society for Testing and Materials ATA American Trucking Associations CTAA Community Transportation Association of America CTBSSP Commercial Truck and Bus Safety Synthesis Program DHS Department of Homeland Security DOE Department of Energy EPA Environmental Protection Agency FAA Federal Aviation Administration FAST Fixing America’s Surface Transportation Act (2015) FHWA Federal Highway Administration FMCSA Federal Motor Carrier Safety Administration FRA Federal Railroad Administration FTA Federal Transit Administration GHSA Governors Highway Safety Association HMCRP Hazardous Materials Cooperative Research Program IEEE Institute of Electrical and Electronics Engineers ISTEA Intermodal Surface Transportation Efficiency Act of 1991 ITE Institute of Transportation Engineers MAP-21 Moving Ahead for Progress in the 21st Century Act (2012) NASA National Aeronautics and Space Administration NASAO National Association of State Aviation Officials NCFRP National Cooperative Freight Research Program NCHRP National Cooperative Highway Research Program NHTSA National Highway Traffic Safety Administration NTSB National Transportation Safety Board PHMSA Pipeline and Hazardous Materials Safety Administration RITA Research and Innovative Technology Administration SAE Society of Automotive Engineers SAFETEA-LU Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (2005) TCRP Transit Cooperative Research Program TDC Transit Development Corporation TEA-21 Transportation Equity Act for the 21st Century (1998) TRB Transportation Research Board TSA Transportation Security Administration U.S. DOT United States Department of Transportation

Traffic Signal Control Strategies for Pedestrians and Bicyclists Transportation Research Board 500 Fifth Street, NW Washington, DC 20001 ADDRESS SERVICE REQUESTED ISBN 978-0-309-09431-3 9 7 8 0 3 0 9 0 9 4 3 1 3 9 0 0 0 0

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In the United States, traffic signal timing is traditionally developed to minimize motor vehicle delay at signalized intersections, with minimal attention paid to the needs of pedestrians and bicyclists. The unintended consequence is often diminished safety and mobility for pedestrians and bicyclists.

The TRB National Cooperative Highway Research Program's NCHRP Research Report 969: Traffic Signal Control Strategies for Pedestrians and Bicyclists is a guidebook that provides tools, performance measures, and policy information to help agencies design and operate signalized intersections in a way that improves safety and service for pedestrians and bicyclists while still meeting the needs of motorized road users.

Supplemental to the report are presentations of preliminary findings, strategies, and summary overview.

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