The Federal Highway Administration has been encouraging states to improve their monitoring and tracking of the mobility impacts of work zones. The use of mobility performance measures will enable agencies to assess better the contribution of work zones to network congestion; to identify specific projects that are in need of remedial action; and potentially to assess penalties to contractors creating excessive, avoidable negative impacts. Although the Virginia Department of Transportation (VDOT) has defined allowable lane closure hours for the interstate system, VDOT has not defined specific performance measures and thresholds for what constitutes unacceptable work zone mobility impacts. Performance measures and thresholds have been developed by a number of other states, so there is a need to determine whether these could be adapted for use by VDOT. This study explored issues related to a potential work zone mobility performance measurement program for Virginia. The issues investigated included identification of potential performance measures, definition of performance thresholds, and recommendations for data sources for performance measurement calculations. This information was synthesized from information regarding the experiences of selected states and experiences from a series of case studies that used data from Virginia work zones. The review of experiences in selected other states found that delay and queue lengths were the performance measures used most often by the states studied. The Virginia case studies focused on the use of private sector data to generate mobility performance measures and found that the level of spatial aggregation in rural areas could inhibit the ability to generate accurate performance measures, although granularity was better on urban roads. The level of temporal aggregation was also found to influence performance measures. The research identified a number of key issues that VDOT should consider as a work zone mobility performance measures program is developed. The report recommends that VDOT develop a pilot program that focuses on urban interstates initially and convene a task group to develop formal policies and procedures for use in the state.

Construction of a Virginia Department of Transportation project to install an Active Traffic Management (ATM) system on I-66 from U.S. 29 in Centreville to the Capital Beltway (I-495) was completed in September 2015. The project was constructed to improve safety and operations on I-66 through better management of existing roadway capacity. The main components of the ATM system were advisory variable speed limits (AVSL), queue warning systems (QWS), lane use control signs (LUCS), and hard shoulder running (HSR). Since ATM is still a relatively new approach in the United States, there was a need to analyze the effects of the I-66 ATM. Thus, a before-and-after study was conducted to quantify its effectiveness. The study used "after" data from October 2015-February 2016 (21 weeks) for the operations analysis and data from October 2015-December 2015 (13 weeks) for the safety analysis. Operations and safety evaluations were performed using limited data, so the results should be considered preliminary. The operational measures of effectiveness (MOEs) included ATM utilization rate, average travel time, travel time reliability, and total travel time delay. The safety MOEs included crash rates by type and severity and incident frequency. These MOEs were analyzed using INRIX travel time data, limited traffic volume point sensor data, police crash reports, and iPeMS traffic incident data. Segment-level analysis was performed to determine the segments that benefitted the most from ATM implementation. From this segment-level analysis, it was determined that HSR was the ATM component that led to most of the improvements on I-66. The results of the study indicate that the ATM produced positive operational and safety benefits across multiple MOEs. The ATM generally had limited operational and safety impacts during the weekday peak periods and some impacts during the midday and off-peak weekday periods. Average weekday travel times during the midday period in the off-peak direction typically improved by 2% to 6%. However, weekday peak period travel times and travel time reliability in the peak direction continued to degrade after ATM installation. This was not surprising given that HSR was already in use during the weekday peak periods before ATM activation and there has been a historic trend of increased travel times on the corridor. There were large operational benefits on weekends, with average travel times and travel time reliability improving by approximately 10% during the weekend peak periods. The weekend improvements were most likely due to the activation of HSR, which had not been active during weekends before ATM implementation, so the additional capacity served to alleviate congestion after activation. The safety analysis showed promising results for weekends, but no solid conclusions could be formed because of the limited data available for the safety analysis. A planning-level benefit-cost ratio was calculated based on the initial operational and safety benefits. The ATM had a benefit-cost ratio of 1.54 based on conservative assumptions that used only weekend operational improvements. This indicates that the I-66 ATM was a cost-efficient solution for improving operations and safety on I-66. The study recommends expansion of ATM in Virginia and further study.

The Federal Highway Administration has been encouraging states to improve their monitoring and tracking of the mobility impacts of work zones. The use of mobility performance measures will enable agencies to assess better the contribution of work zones to network congestion; to identify specific projects that are in need of remedial action; and potentially to assess penalties to contractors creating excessive, avoidable negative impacts. Although the Virginia Department of Transportation (VDOT) has defined allowable lane closure hours for the interstate system, VDOT has not defined specific performance measures and thresholds for what constitutes unacceptable work zone mobility impacts. Performance measures and thresholds have been developed by a number of other states, so there is a need to determine whether these could be adapted for use by VDOT. This study explored issues related to a potential work zone mobility performance measurement program for Virginia. The issues investigated included identification of potential performance measures, definition of performance thresholds, and recommendations for data sources for performance measurement calculations. This information was synthesized from information regarding the experiences of selected states and experiences from a series of case studies that used data from Virginia work zones. The review of experiences in selected other states found that delay and queue lengths were the performance measures used most often by the states studied. The Virginia case studies focused on the use of private sector data to generate mobility performance measures and found that the level of spatial aggregation in rural areas could inhibit the ability to generate accurate performance measures, although granularity was better on urban roads. The level of temporal aggregation was also found to influence performance measures. The research identified a number of key issues that VDOT should consider as a work zone mobility performance measures program is developed. The report recommends that VDOT develop a pilot program that focuses on urban interstates initially and convene a task group to develop formal policies and procedures for use in the state.

The objective of the study was to evaluate the safety effects of two countermeasures with respect to vehicle–pedestrian crashes—the provision of protected or protected/permissive left-turn phasing and the provision of leading pedestrian intervals (LPIs)—using a before–after empirical Bayesian methodology. The study used data from North American cities that had installed one or both of the countermeasures of interest, including Chicago, IL; New York City, NY; Charlotte, NC; and Toronto, ON. This study showed that the provision of protected left-turn phasing reduced vehicle–vehicle injury crashes but did not produce statistically significant results for vehicle–pedestrian crashes overall. A disaggregate analysis of the effect of protected or protected/permissive left-turn phasing on vehicle–pedestrian crashes indicated that this strategy may be more beneficial when there are higher pedestrian and vehicle volumes, particularly above 5,500 pedestrians per day. At these high-volume locations, the left-turn phasing evaluation resulted in a potential benefit–cost (B/C) ratio range of 1:15.6::1:38.9. The evaluation of LPIs showed that the countermeasure reduced vehicle–pedestrian crashes. This evaluation produced a crash modification factor of 0.87 with a potential B/C ratio range of 1:207::1:517.