Strategies for Work Zone Transportation Management Plans (2020)

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168 Motorist Information Strategies Motorist information strategies provide road users with current or real-time information regarding the project work zone. This section covers three motorist information strategies: • Speed feedback signs • Construction truck entering and exiting system • Real-time travel system 10.1 Speed Feedback Signs 10.1.1 Description Speed feedback signs are electronic signs that use vehicle speed-sensing technology to detect and display a vehicle’s current speed to the driver. The vehicle speed is usually displayed along with the regulatory speed with or without a message alerting the drivers to use caution. There are two types of speed feedback signs: 1. Dynamic speed display signs. An electronic LED display is activated by radar or some type of speed-sensing device and then displays, to approaching drivers, the speed at which they are traveling. Dynamic speed display signs (DSDSs) are typically installed in conjunction with a regulatory black-and-white speed limit sign mounted above the display. DSDSs are commonly referred to as “your speed is” signs, “driver feedback signs,” “speed feedback signs,” “speed display trailers,” “radar speed display,” or “speed monitoring devices.” A DSDS can be fabricated as a separate static sign and dynamic display, or, as Figure 10.1 shows, a single static sign and dynamic display. 2. PCMS with radar. A PCMS fitted with a radar sensor (PCMR) detects the speed of passing vehicles and activates when the speed of a vehicle exceeds a preset threshold value. Based on the specific radar speed, the PCMR is often programmed to display different messages. The radar sensor calculates the speed of passing vehicles in real time and the PCMS displays a message based on the driver’s speed. Common messages displayed include • YOUR SPEED X MPH/SLOW DOWN, • REDUCE SPEED IN WORK ZONE, and • EXCESSIVE SPEED/FINES DOUBLE. Figure 10.1 shows a typical PCMR. 10.1.2 When to Use Speed feedback signs are recommended for use under the following conditions (MnDOT 2019; FHWA 2015; Veneziano et al. 2012): C H A P T E R 1 0

Motorist Information Strategies 169 • When the mean speeds or 85th percentile speeds exceed the PSL by at least 10 mph. • When hazardous roadway conditions, such as a temporary unusually tight curve or a rough road surface, which require extra driving precautions, are present. • When workers are directly adjacent to travel lanes and a lane or portion thereof is closed to traffic without protection of positive barrier. • When the work zone increases or is perceived to increase speeding-related crashes. Use of the speed feedback signs is not limited to any certain PSL value; however, they may have better utility in areas with higher speeds. While speed feedback signs may be used on all types of highways and work zones, in either rural or urban environments, in multilane applications with moderate-to-heavy traffic, it may be unclear which vehicle’s speed is being displayed. Consequently, speed feedback signs are best suited for use on roadways with a maximum of two lanes in each direction. 10.1.3 Benefits The use of speed feedback signs provides the following benefits: • Reduces the speed of vehicles traveling through a work zone. • Encourages speed limit compliance. • Creates uniform speeds throughout the work area. • Improves the overall safety of workers and the traveling public. The DSDS has the option to store the vehicle speed data for use later. This is a major benefit when determining actual speeds in work zones. 10.1.4 Expected Effectiveness Studies have shown that speed feedback signs result in drivers reducing their speed. A wide range of speed-reduction results has been found in the field. • Results of DSDS field studies: – 8–9 mph reduction in mean speeds (Teng et al. 2009). – 0.9–3.1 mph reduction in mean speeds and 2–4 mph reduction in 85th percentile speeds (Brewer, Pesti, and Schneider 2005). DSDS (Credit: Ohio DOT) PCMR (Credit: Arizona DOT) Figure 10.1. DSDS (left) and PCMR (right).

170 Strategies for Work Zone Transportation Management Plans – 3.7 mph reduction in mean speeds (Meyer 2003). – 3–4 mph reduction in mean speeds and 2–7 mph reduction in the 85th percentile speeds, approximately 20 percent to 40 percent increase in vehicles complying with PSL (Pesti and McCoy 2001). – 1.5–9 mph reduction in passenger automobile mean speeds and 3–10 mph reduction in truck mean speeds (Fontaine and Carlson 2001). – 2.9–3.8 mph reduction in mean speeds, 5 mph reduction in 85th percentile speeds, and about 12 percent increase in percentage of vehicles complying with speed limit (Maze 2000). • Results of PCMR field studies: – 2 mph reduction in both observed mean and 85th percentile speeds (Roberts and Smaglik 2014). – 3–7 mph average speed reduction (Ravani et al. 2012). – 1.1–9.8 mph reductions in mean speeds and 2–11.5 mph reductions in 85th percentile speeds (Kenjale 2006). – 7 mph reduction in mean speeds and 5 mph for 85th percentile speeds (Sarasua et al. 2006). – 0.6–2.5 mph reduction in average speeds (GDOT 2005). – 1.6–2.1 mph reduction in automobile mean speeds and 1.3 mph reduction for trucks; 85th percentile speeds reduced by 2 mph for automobiles and by 1 mph for trucks (Brewer, Pesti, and Schneider 2005). – 5–8 mph reduction in speeds (Dixon and Wang 2002). 10.1.5 Crash Modification Factor The CMF for a work zone DSDS is shown in Table 10.1. More information on development of WZCMFs can be found in Chapter 13. 10.1.6 Implementation Considerations Speed feedback signs are placed adjacent to the work zone speed limit sign and in advance of roadway conditions that require speed reduction. It is advisable to place the speed feedback sign on a tangent section of roadway between 1,000 and 2,500 ft upstream of the work activity or hazardous condition. Long work zones (>1 mi) may warrant the deployment of two or more speed feedback signs or the relocation of one sign several times nearer the active work area to improve its effective- ness. For long-term deployments, a solar-powered speed feedback sign may be considered if a fixed power supply source is not available. Speed feedback signs are preferred for short-term use (<30 days). However, if the signs are going to be active for several weeks, periodic police enforcement may be considered to maintain their effectiveness. Crash Type Crash Severity Facility Type Volume Range CMF Standard Error All All Not specified Not specified 0.54 0.2 NOTE: While speed feedback displays may be used to manage work zone speeds, there were no studies available that examined safety effects in work zones specifically. The CMF was derived from a meta-analysis of past studies on non–work zone roads, so its applicability to a work zone situation is unclear. CMF = crash modification factor; DSDSs = dynamic speed display signs. Table 10.1. CMFs for DSDSs.

Motorist Information Strategies 171 10.1.7 Design Features and Requirements Each time a speed feedback sign is set up, the speed measuring device must be checked and adjusted (if necessary) to ensure accuracy. Speed measuring devices should provide a minimum detection distance of 1,000 ft and must have an accuracy of ±1 mph. The speed feedback sign should remain blank when no traffic is detected. For speeds detected over a set maximum speed (generally 10 mph over the PSL on low-speed roadways [<45 mph] and 20 mph over on high-speed roadways [>45 mph]), the display should go blank. This measure is intended to discourage drivers from seeing how fast they can get the speed display trailer to read. The display must be amber with a black background and dim automatically for nighttime operations. The DSDS mounting height, lateral offset, and orientation must conform to applicable guidelines from the 2009 MUTCD, Sections 2A.18, 2A.19, and 2A.20. The digital speed display must show two digits (00 to 99) in mph, and the lowest portion of the display should be high enough to be visible over concrete barriers or safety drums. Speed feedback sign placement should be incorporated at the project design stage to ensure signs are placed in a safe location with adequate driver visibility. 10.1.8 State of the Practice DSDSs are used frequently in Illinois, Iowa, Minnesota, Oregon, and Washington. In 2014, IDOT began requiring contractors to furnish a DSDS whenever workers are present and lanes are restricted by construction. The speed display trailer special provisions for Illinois and Iowa are attached as Appendix I1 and I2, respectively. The use of PCMRs is infrequent, and literature shows their use limited to pilot projects in Arizona, California, Maryland, Oregon, and Washington. 10.1.9 Cost A DSDS ranges between $7,000 and $10,000. Upper-cost DSDSs include flashing lights with an electronic message such as “SLOW DOWN.” For an additional $5,000, data collection with storage capability can be included. A PCMR ranges between $10,000 and $12,000. 10.1.10 Resources and References 10.1.10.1 DSDS Chen, Y., X. Qin, and D. A. Noyce. Evaluation of Strategies to Manage Speed in Highway Work Zones. Presented at 86th Annual Meeting of the Transportation Research Board, Washington, D.C., 2007. Chowdhury, T. D., and O. A. Abaza. Effectiveness of VSL Signs in Reducing Crash Rates on Roadway Construction Work Zones in Alaska, 19th International Conference on Traffic Guidance and Transportation, New York, October 5–6, 2017. Cruzado, I., and E. T. Donnell. Evaluating Effectiveness of Dynamic Speed Display Signs in Transition Zones of Two-Lane, Rural Highways in Pennsylvania, Pennsylvania State University, Traffic Control Devices, Visibility, and Highway-Rail Grade Crossings, Vol. 2122/2009, pp. 1–8, Transportation Research Record: Journal of the Transportation Research Board, No. 0361-1981, December 2009.

172 Strategies for Work Zone Transportation Management Plans Edara, P., C. Sun, C. Keller, and Y. Hou. Evaluating the Benefits of Dynamic Message Signs on Missouri’s Rural Corridors, CMR 13-004, Missouri Department of Transportation, December 2011. FHWA. Planning Guidance for Intelligent Transportation Systems (ITS) Devices, FHWA-JPO-14-14,5 Enterprise Transportation Pooled Fund Study TPF-5 (231), U.S. DOT, September 2015. Fontaine, M. D., and P. J. Carlson. Evaluation of Speed Displays and Rumble Strips at Rural-Maintenance Work Zones. Transportation Research Record: Journal of the Transportation Research Board, No. 1745, 2001, pp. 27–38. Gambatese, J. A., and A. Jafarnejad. Evaluation of Radar Speed Display for Mobile Maintenance Operations, OR-RD-16-09, Oregon Department of Transportation, December 2015. Gambatese, J., and F. Zhang. Safe and Effective Speed Reductions for Freeway Work Zones Phase 2, FHWA- OR-RD-15-04, Oregon Department of Transportation, September 2014. Gambatese, J. A., and F. Zhang. Safe and Effective Speed Reductions for Freeway Work Zones Phase 3, FHWA- OR-RD-15-09, Final Report, Implementation Research, Oregon Department of Transportation, 2015. Jeihani, M., A. Ardeshiri, and A. Naeeni. Evaluating the Effectiveness of Dynamic Speed Display Signs, Morgan State University, September 2012. Maze, T. Speed Monitor Display, Iowa State University, Midwest States Smart Work Zone Deployment Initiative, 2000. McAvoy, D. S. Work Zone Speed Reduction Utilizing Dynamic Speed Signs, Ohio University, 2011. Meyer, E. Radar Speed Display, Midwest States Smart Work Zone Deployment Initiative, 2003. MnDOT. Intelligent Work Zone Toolbox, Office of Traffic, Safety, and Operations, Minnesota Department of Transportation, 2019. Manual on Uniform Traffic Control Devices. FHWA, U.S. DOT, 2009. http://mutcd.fhwa.dot.gov/. [MUTCD] Pesti, G., and P. T. McCoy. Long-Term Effectiveness of Speed Monitoring Displays in Work Zones on Rural Interstate Highways. Transportation Research Record: Journal of the Transportation Research Board, No. 1754, 2001, pp. 21–30. Teng, H., X. Xu, X. Li, V. Kwigizile, and A. R. Gibby. Evaluating of Speed Monitoring Displays for Work Zones in Las Vegas, Nevada, University of Nevada, Volume 2107 / 2009 Safety Maintenance and Surface Weather, Transportation Research Record: Journal of the Transportation Research Board, No. 036-1981, October 2009, pp. 46–56. Veneziano, D., Z. Ye, K. Westoby, I. Turnbull, and L. Hayden. Guidance for Radar Speed Sign Deployments. Presented at 91st Annual Meeting of the Transportation Research Board, Washington, D.C., 2012. 10.1.10.2 PCMR Brewer, M. A., G. Pesti, and W. H. Schneider IV. Identification and Testing of Measures to Improve Work Zone Speed Limit Compliance, Texas A&M Transportation Institute, Report 0-4707-1, October 2005. Dixon, K., and C. Wang. Development of Speed Reduction Strategies for Highway Work Zones, FHWA-GA-02-9810, Georgia Department of Transportation, July 2002. Garber, N. J., and S. T. Patel. Effectiveness of Changeable Message Signs in Controlling Vehicle Speeds in Work Zones, Virginia Transportation Research Council, FHWA/VA-95-R4, September 1994. Garber, N. J., and S. Srinivasan. Effectiveness of Changeable Message Signs in Controlling Vehicle Speeds in Work Zones: Phase II, VTRC 98-R10, Virginia Transportation Research Council, December 1998. GDOT. Evaluating Speed Reduction Strategies for Highway Work Zones (Smart Work Zones), Georgia Department of Transportation, January 2005. Kenjale, A. D. Use of Speed Monitoring Display with Changeable Message Sign to Reduce Vehicle Speeds in SC Work Zones, All Theses, Paper 49, 2006. Ravani B., C. Wang, W. A. White, and P. Fyhrie. Evaluation of Methods to Reduce Speed in Work Zones, AHMCT Research Center, University of California–Davis, 2012. Roberts, C. A., and E. J. Smaglik. Reduction of Speed in Work Zones Using ITS DMS Instant Feedback to Drivers: Vehicle Speed Versus Traffic Fine, FHWA-AZ-14-681, Arizona Department of Transportation, August 2014. Sarasua, W. A., J. H. Ogle, W. J. Davis, and M. Chowdhury. Better Management for Speed Control in Work Zones, FHWA-SC-06-10, South Carolina Department of Transportation, December 2006. 10.2 Construction Truck Entering and Exiting System 10.2.1. Description A construction truck entering and exiting system is a SWZ system that automatically detects when construction vehicles enter or exit the work zone and provides advanced notification to motorists (Figure 10.2). The system works in real time and only activates when a construction

Motorist Information Strategies 173 vehicle is entering or exiting a work zone. When a traffic sensor detects a construction vehicle either entering or exiting, motorists are alerted of a truck slowing down or entering the flow of traffic via either a PCMS or flashing static signs. 10.2.2. When to Use WisDOT, in its FDM 11-50-5 TMP Process, lists the following criteria for consideration when determining if a truck entering and exit system should be installed: • A construction vehicle uses a live traffic lane to either decelerate or accelerate because a deceleration or acceleration lane cannot be provided. • The construction stage will be in place for an extended period. • The construction entrance is visibly obscured to drivers. According to the MnDOT Intelligent Work Zone Toolbox (2019 edition), a truck entering and exiting system should be considered for work zones under the following conditions: • The trucks must utilize the main-line roadway to accelerate. • A truck merge lane cannot be provided on the project. • There is a sight restriction where trucks must enter the open traffic lane. • There is insufficient space for a truck acceleration lane before entering the open traffic lane. • Trucks must decelerate in the main-line roadway to enter the work space. This may result in vehicles following trucks into the work space, or traffic being required to adjust speed or change lanes. • ADT on the roadway is above the level at which truck drivers can easily find a gap in traffic and accelerate within the traffic lane without causing traffic to suddenly adjust speed or change lanes. Figure 10.2. Construction truck entering and exiting system layout (Credit: MnDOT).

174 Strategies for Work Zone Transportation Management Plans 10.2.3 Benefits The use of a construction truck entering and exiting system provides the following benefits: • Alerting motorists of slow construction vehicles entering and exiting the work zone. • Reducing the frequency of motorists following construction vehicles into the work zone. • Reducing rear-end crashes caused by abrupt slowdowns. 10.2.4 Expected Effectiveness Research found no published literature relating to field evaluations of construction truck entering and exiting systems. 10.2.5 Crash Modification Factor A CMF is not applicable for this strategy. 10.2.6 Implementation Considerations Deployment consideration will address estimated traffic volumes, the type of vehicle conflicts anticipated, and project geometrics such as the merging, stopping, and site distance for the travelers to the hazardous condition. The system needs to be timed such that a PCMS message is viewable and understandable to drivers, and the traveler can perform appropriate evasive actions, such as slowing down and stopping, changing lanes, or changing travel routes. An appropriate PCMS distance will allow drivers time to change lanes or to slow appropriately to allow the truck to merge. One issue is how to distinguish between construction trucks and all other equipment that moves within the work zone so that false triggers do not occur. This can be handled by carefully limiting the detection zone. 10.2.7 Design Features and Requirements A basic system consists of a portable traffic sensor to detect construction vehicles, a PCMS, and a wireless communication link to trigger the sign. These systems are typically stand-alone, so they do not usually have a link to a TMC. Communication between the construction vehicle detector and the PCMS must occur in real time (milliseconds). Therefore, a point-to-point wireless transmission must be used as the transmission times for cellular communications are not fast enough. Agencies can use a static sign option as well for trucks entering traffic, which would include individual beacons attached at the top of the sign that would flash when a truck is entering or exiting the main line. 10.2.8 State of the Practice A construction truck entering and exiting system is one technology application promoted by the FHWA SWZ, as part of the FHWA EDC initiative. Many resources, including bid speci- fications, deployment plans, and case studies, are available on the National Work Zone Safety Information Clearinghouse (https://www.workzonesafety.org/swz/). States using these systems include Colorado, Iowa, Michigan, Minnesota, Ohio, and Texas. The Gap is an 18-mi stretch of Interstate 25 in Colorado, running from south of Castle Rock to Monument. It is the only four-lane section of I-25, connecting Colorado’s two largest

Motorist Information Strategies 175 cities—Denver and Colorado Springs. On average, nearly 80,000 vehicles travel the I-25 South Gap corridor daily with delays and crashes a common occurrence. Construction on the $350 million project, which is currently the longest construction zone in the state, began in Fall 2018; project completion is scheduled for 2022. With an average of three trucks delivering or picking up material every 5 minutes daily throughout the 18-mi work zone, CDOT deployed a construction truck entering and exiting system to warn drivers. When a construction truck passed a sensor attached to a portable sign, a PCMS (Figure 10.3) further back in the corridor was triggered to warn motorists to slow down and yield to the truck. 10.2.9 Cost The cost for deployment of a truck warning system depends highly on the project duration and the number of devices used (e.g., message boards, traffic sensors, speed trailers, cameras). In general, the rental cost is the same for a PCMS or a traffic sensor or camera—approximately $1,000 per week. For longer-duration projects, the rental costs can be substantially lower. MnDOT reported the cost estimate, based on 2018 MnDOT rental prices, for a truck warning system using 1 PCMS and 1 sensor at $2,000 per week, $3,500 per month, or $13,000 per 6 months (MnDOT 2018). MnDOT also reported an approximate cost of $44,000 (or 0.37 percent of the total construction cost) for a truck warning system utilizing 6 PCMSs, 6 sensors, and 16 advance flashers deployed over 6 months. Similarly, Hawaii DOT reported an approximate cost of $400,000 (or 0.05 percent of total construction cost) for a truck warning system that deployed 8 PCMSs, 15 sensors, and a license plate reader system (TxDOT 2018). 10.2.10 Resources and References FHWA Every Day Counts (EDC) Initiative: SWZs, Technology Applications: Entering/Exiting Vehicle Notifi- cation web page. https://www.workzonesafety.org/swz/swztechnology-application/types-of-applications/ enteringexiting-vehicle-notification/. MnDOT. Intelligent Work Zone Toolbox, Office of Traffic, Safety, and Operations, Minnesota Department of Transportation, 2019. MnDOT. Cost Estimates for ITS/IWZ Scoping, June 6, 2018, https://www.dot.state.mn.us/its/docs/scoping decisiontree.pdf, accessed May 26, 2020. Figure 10.3. I-25 Construction truck warning system (Credit: CDOT).

176 Strategies for Work Zone Transportation Management Plans TxDOT. Smart Work Zone Guidelines: Design Guidelines for Deployment of Work Zone Intelligent Transportation Systems (ITS), Texas Department of Transportation, October 2018. WisDOT. Facilities Development Manual (FDM) 11-50-5 Transportation Management Plan Process, Wisconsin Department of Transportation, May 15, 2019. 10.3 Real-Time Travel System 10.3.1 Description A real-time travel system (RTTS), also known as a travel time system, a work zone information system, or a travel time information and prediction system, is a portable automated system that predicts and displays travel time for motorists in advance of and through freeway construction work zones on a real-time basis (Figure 10.4). RTTSs use roadside sensors to collect real-time traffic-flow data, process the data, calculate estimated travel time between different points on the freeway, and display travel time information on several portable electronic CMSs positioned at predetermined locations along the freeway. Figure 10.4. Real-time travel system layout (Credit: MnDOT).

Motorist Information Strategies 177 In general, the system would display a message to travelers that, from their current location, it will take X minutes to reach a given location ahead of them (e.g., Hwy 23/25 miles/35 mins). 10.3.2 When to Use RTTS may be considered for use under the following situations: • The work zone may cause 10 minutes or more of additional travel time. • The work zone causing the delay is more than 5 mi beyond the PCMS location (preferably 10 mi or more, such that multiple alternate routes are available). Long-term projects are more ideal situations for using RTTSs because the system costs will be more easily justified. However, any situation that necessitates communication with drivers while they are in or approaching a work zone may be appropriate for RTTS applications. NJDOT developed warrants as a guideline for determining the suitability of an RTTS. If the total score is less than 35, an RTTS should not be deployed. Scores between 35 and 45 should be reviewed by the executive manager of mobility and systems engineering. Scores above 45 should have an RTTS deployed as part of the contract. Table 10.2 shows the NJDOT warrants and their corresponding scoring criteria for RTTS. 10.3.3 Benefits By obtaining traffic information and displaying travel times to motorists, an RTTS allows motorists to make an informed decision on which routes to take. If travel times are long because of roadwork or an incident, motorists can use an alternate route, thus reducing demand on the route. By providing motorists with traffic-condition information, the system also reduces the stress and anxiety caused by congested conditions. Although an RTTS is not directly an operational TTC device for a project, as it provides no direct traffic control, DOTs might consider it for deployment as part of an agency’s public relations and traveler information system. An RTTS is extremely useful where construction will create long vehicle delays for extended periods of time, and it may persuade some travelers to use alternate routes. 10.3.4 Expected Effectiveness The use of RTTS in work zones has been studied extensively with the following results: • Reductions of more than 30 percent in deceleration rates (Hourdos 2019). • 28 percent motorist diversion on seeing an RTTS (Luttrell et al. 2008). • 9 percent diversion during peak hour and benefit–cost ratio between 2.1:1 and 3.2:1 (Edara, Sun, and Hou 2013). • MDSHA real-time Travel Time Prediction System (ARAMPS). – 92 percent accuracy in travel time prediction during both morning and evening peak periods (Chang, Zou, and Wang 2006). • Automated Work Zone Information System – 95 percent accuracy in travel time prediction and 7 percent–21 percent increase in alternate route selection (Lee and Kim 2006). • Traffic information and prediction system – 28 percent–41 percent accuracy in travel time prediction (Pigman and Agent 2004). – 88 percent accuracy in travel time prediction within ±4 minutes, 65 percent–70 percent accuracy within ±2 minutes (Zwahlen and Russ 2002).

178 Strategies for Work Zone Transportation Management Plans 10.3.5 Crash Modification Factor No CMF is applicable for this strategy. 10.3.6 Implementation Considerations The following aspects might also be considered when deploying RTTS: • DOTs can integrate RTTS with a regional TMC or other state and project websites. • Costs associated with the purchase or lease of RTTS components can be significant. No. Condition Scoring Criteria and Point Score 1 Based on proposed work zone, will there be a long-term loss of traveled lane continuously for 3 or more months?a Yes: 10 points No: 0 points 2 Based on proposed work zone, will there be a temporary loss of traveled lane continuously for 3 or more months?b Yes: 10 points for 6 hours of the day 9 points for 5 hours of the day, etc. No: 0 3 Does section of the highway containing proposed work zones include parallel local and express lanes? Yes: 10 No: 0 4 Are viable alternate routes available so motorists can avoid work zone? Freeway: 10 US route: 7 State route: 5 Local road: 3 No: 0 5 Does one-way AADT or ADT exceed 60,000 in the direction of proposed work zone?c Yes: 1 × each 10,000 above 60,000 6 Does traffic volume per lane exceed 1,500 vph during day?d Yes: 1 × each 100 over 1,500 7 Will traffic volume exceed 1,500 vphpl in the remaining lanes if answer to question 1 is an affirmative?e Yes: 1 × each 100 over 1,500 8 Is highway section containing proposed work zone a known location of congestion for the congestion management system? Makes top 10: 10 Makes top 20: 9 Makes top 30: 8, etc. 9 Is section of the work zone near major traffic generators?f Based on severity: 0–5 Seasonal: 10 10 Is work zone proposing temporary bridge, contraflow lanes, or cattle chute? Based on complexity: 0–5 Total Score NOTE: aThis includes the conditions in which a traveled lane is lost permanently from the proposed work zone and continuously for an extended period of time. (Loss of highway lane continuously for 3 months). bThis includes the condition where the loss of highway lane is temporary, limited to peak periods of the day, and only for an extended period of time. (Loss of highway lane only during certain hours of the day for an extended period of time.) cIf AADT is not available, determine the ADT based on the nearest section of the highway where 24 hours volume was recorded. The information needs to be based on an average of at least three regular weekdays during the months when schools are in session. If the information is not available, use 10. dIf per-lane volume information is not available, divide the highest volume of any peak hour during the day (6:00 a.m.–8:00 p.m.) by the number of highway lanes in the section of the work zone. eIf the proposed work zone will reduce the number of lanes, divide the highway volumes through the work zone by the number of remaining available lanes. fIf the roadway section is near major traffic generators, such as shopping malls, office complexes, etc. For recreational or seasonal traffic generators, use 10. AADT = annual average daily traffic; ADT = average daily traffic; vph = vehicles per hour; vphpl = vehicles per hour per lane. SOURCE: NJDOT, Mobility and Systems Engineering, Operations Bulletin No. 006B, 2013. Table 10.2. NJDOT warrants for RTTS.

Motorist Information Strategies 179 • Agencies will need to perform comprehensive testing of the system. • An RTTS may also be supplemented with other informational devices such as a highway advisory radio. 10.3.7 Design Features and Requirements The RTTS consists, at a minimum, of the following: • Sensors to monitor and record traffic data. • A PCMS to display real-time messaging to the general public. It is important to design primary locations for the messaging so that travelers may choose alternate routes based on the displayed time for their planned route. Secondary locations for messaging would provide the traveler with travel time information. Although alternate routes cannot be taken from secondary locations, travelers will be provided with real-time information about their traffic delay situation. 10.3.8 State of the Practice RTTS is one of the technology applications promoted by the FHWA’s SWZ during Round 3 of the EDC initiative. Many resources, including bid specifications, deployment plans, and case studies, are available on the National Work Zone Safety Information Clearinghouse website (https://www.workzonesafety.org/swz/). Arizona, Illinois, Iowa, Ohio, Michigan, and Minnesota use RTTSs on certain corridors continuously as a standard practice, increasing the exposure of the motoring public to this concept. These states have mature systems that generate accurate and dependable results. 10.3.8.1 Maricopa County Department of Transportation For Round 3 of the FHWA EDC initiative, the Maricopa County Department of Trans- portation (MCDOT) developed an SWZ technical feasibility concept for arterial roadways (Kimley-Horn 2016). The agency developed a general concept that identified the compo- nents to be used at all MCDOT SWZ deployments, regardless of the specific characteristics of the work zone (length, location, duration, etc.). The recommended devices and order of core components for MCDOT work zones are not expected to change. However, it is expected that the actual location of each component in the work zone will be based on the specific characteristics of the work zone and the roadway in question. Figure 10.5 depicts the core components and their relevant order for deployment in all MCDOT work zones. In March 2019, MCDOT piloted the SWZ concept using an RTTS on the MC-85 reconstruc- tion of arterial roadways for 3 months. Alternative routing was an important goal for this SWZ deployment. The MCDOT TMC monitored all system operations, examining and overriding variable messages, monitoring and changing traffic signal operations, responding to alerts from the system, and coordinating with all partners as part of the project. Figure 10.6 provides the layout where specific technologies were placed to support the MC-85 work zone Phase 1 initiative in both directions. At the time this guidebook was written, MCDOT was conducting a performance evaluation of the SWZ deployment system from both an operational standpoint (how well devices are working) and a benefits standpoint (whether SWZ goals are being met). 10.3.8.2 Louisiana An RTTS was deployed during reconstruction of the Israel LaFleur Bridge (I-210) in 2018 to maintain the bridge’s integrity and extend its life. As expected, the work led to an increase

180 Strategies for Work Zone Transportation Management Plans in traffic congestion along I-210, I-10, and the area surrounding Lake Charles. Twenty-three PCMSs that contained alternative route messages, travel time messages, or both—positioned 2 to 20 mi before the actual work zone—were deployed on this project. 10.3.8.3 Minnesota During Summer 2012, three large construction projects occurred along a 70-mi stretch of I-35 between Hinckley and Duluth, Minnesota. MN-23, which runs parallel to I-35, was designated as an alternate route to help reduce congestion on I-35 during peak travel periods. Figure 10.7 illustrates the extent of the project area. To provide motorists with travel time information in the construction work zones, MnDOT deployed an RTTS consisting of 7 roadside static signs with inserted changeable modules that Figure 10.5. MCDOT smart work zone concept layout (Credit: MCDOT). Figure 10.6. MCDOT smart work zone components during MC-85 reconstruction (Credit: MCDOT).

Motorist Information Strategies 181 displayed real-time travel times to motorists. The RTTS was in operation 24/7 with updates to the travel time signs occurring every 5 minutes. 10.3.9 Cost The cost for deploying an SWZ, such as the RTTS, depends on the project duration and the number of devices (e.g., message boards, traffic sensors, speed trailers, cameras) used. In general, the rental cost is the same for a PCMS or a traffic sensor or camera—approximately $1,000 per week. For longer-duration projects, the rental costs can be substantially lower. WisDOT reported a cost estimate for an RTTS project that used 14 PCMSs, 16 sensors, and 2 cameras to be $113,000 for 5 months in 2017 (TxDOT 2018). TxDOT estimated RTTS deployment costs in 2015 on a project involving 8 PCMSs, 8 sensors, 8 trailers, and 8 cameras at $835,690 for 34 months (or 1 percent of total construction cost). TxDOT in 2016 estimated a project involving 4 PCMSs, 8 sensors, 4 trailers, and 4 cameras at $410,000 for 24 months (∼1 percent of total construction cost). 10.3.10 Resources and References Bushman, R., and C. Berthelot. Response of North Carolina Motorists to a Smart Work Zone System. Presented at 84th Annual Meeting of the Transportation Research Board, Washington, D.C., 2005. Chang, G. L., and K. P. Kang. Evaluation of Intelligent Transportation System Deployments for Work Zone Operations, Maryland State Highway Administration, August 2005. Chang, G. L., N. Zou, and J. Wang. Development and Field Evaluation of a Real-Time Travel Time Prediction System, Maryland State Highway Administration, MD-07-SP508B4D, December 2006. Chen, Y., X. Qin, and D. A. Noyce. Evaluation of ATIS in Suburban Freeway Work Zone, Presented at the ITS America Annual Conference and Exposition, New York, November 16–20, 2008. Chu, L., H. K. Kim, Y. Chung, and W. Recker. Evaluation of Effectiveness of Automated Work Zone Information Systems. Transportation Research Record: Journal of the Transportation Research Board, No. 1911, 2005, pp. 73–81. Edara, P., C. Sun, and Y. Hou. Effectiveness of Work Zone Intelligent Transportation Systems, University of Missouri–Columbia, InTrans Project 06-277, December 2013. FHWA Every Day Counts (EDC) Initiative: Smarter Work Zones, Technology Applications: Real-Time Traveler Information web page. https://www.workzonesafety.org/swz/swztechnology-application/types-of- applications/real-time-traveler-information/. Figure 10.7. I-35 project location and RTTS signs (Credit: FHWA).

182 Strategies for Work Zone Transportation Management Plans Hourdos, J. Evaluation of the Smart Work Zone Speed Notification System, Minnesota Department of Trans- portation, June 2019. Kimley-Horn and Associates, Inc. MCDOT Smart Work Zone Technical Feasibility Concept Document, Maricopa County, Arizona, Department of Transportation, June 2016. Lee, E., and C. Kim. Automated Work Zone Information System on Urban Freeway Rehabilitation: California Implementation. Transportation Research Record: Journal of the Transportation Research Board, No. 1948, 2006, pp. 77–85. Luttrell, T., M. Robinson, J. Rephlo, R. Haas, J. Srour, R. Benekohal, J-S Oh., and T. Scriba. The Benefits of Using Intelligent Transportation Systems in Work Zones: A Summary Report, FHWA-HOP-08-021, FHWA, U.S. DOT, April 2008. Meyer, E., Construction Area Late Merge (CALM) System. Midwest Smart Work Zone Deployment Initiative Project Year 2002 Evaluations. Kansas Department of Transportation, Topeka, 2004. Pigman, J. G., and K. R. Agent. Evaluation of Traffic Information and Prediction System (TIPS) as Work Zone Traffic Control, Research Report KTC-04-10/FR128-03-1F, Kentucky Transportation Center, University of Kentucky, March 2004. Savolainen, P. T., D. S. McAvoy, V. Reddy, J. B. Santos, and T. K. Datta. Evaluation of Motorist Awareness System. Presented at 88th Annual Meeting of the Transportation Research Board, Washington, D.C., 2009. Tudor, H. L., A. Meadors, and R. Plant. Deployment of Smart Work Zone Technology in Arkansas. Presented at 82nd Annual Meeting of the Transportation Research Board, Washington, D.C., 2002. TxDOT. Smart Work Zone Guidelines: Design Guidelines for Deployment of Work Zone Intelligent Transportation Systems (ITS), Texas Department of Transportation, October 2018. Zwahlen, H. T., and A. Russ. Evaluation of the Accuracy of a Real-Time Travel Time Prediction System in a Freeway Construction Work Zone. Transportation Research Record: Journal of the Transportation Research Board, No. 1803, 2002, pp. 87–93.