This study uses a suite of performance measures that was developed by taking into consideration various aspects of congestion and reliability, to assess impacts of safety projects on congestion. Safety projects are necessary to help move Virginia’s roadways toward safer operation, but can contribute to congestion and unreliability during execution, and can affect operations after execution. However, safety projects are assessed primarily for safety improvements, not for congestion. This study identifies an appropriate suite of measures, and quantifies and compares the congestion and reliability impacts of safety projects on roadways for the periods before, during, and after project execution. The paper presents the performance measures, examines their sensitivity based on operating conditions, defines thresholds for congestion and reliability, and demonstrates the measures using a set of Virginia safety projects. The data set consists of 10 projects totalling 92 mi and more than 1M data points. The study found that, overall, safety projects tended to have a positive impact on congestion and reliability after completion, and the congestion variability measures were sensitive to the threshold of reliability. The study concludes with practical recommendations for primary measures that may be used to measure overall impacts of safety projects: percent vehicle miles traveled (VMT) reliable with a customized threshold for Virginia; percent VMT delayed; and time to travel 10 mi. However, caution should be used when applying the results directly to other situations, because of the limited number of projects used in the study.
KimleyH.VDOT Performance Measures Synthesis Report. Internal Draft Report (Unpublished). 2019. The following agencies and sources of information were reviewed:”
3.
○ District Department of Transportation (DDOT). District Mobility Data Analysis Methodology (At the time of writing this paper DDOT mobility website appears to have expired CA certificates, therefore URL is not provided)
4.
○ District Department of Transportation (DDOT). District Mobility Project, January2017 (At the time of writing this paper DDOT mobility website appears to have expired CA certificates, therefore URL is not provided)
○ Georgia Department of Transportation (GDOT). GDOT Regional Traffic Operations Program (RTOP) and Automated Traffic Signal Performance Measure (ATSPM) (This is based on Kimley-Horn’s work with GDOT therefore URL not provided)
○ National Academies of Sciences, Engineering, and Medicine2011. NCHRP Report 708: A Guide for Sustainability Performance Measurement for Agencies. The National Academies Press, Washington, D.C.https://doi.org/10.17226/14598
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○ National Academies of Sciences, Engineering, and Medicine2004. NCHRP Project 20-24(30) Report: Performance Measures for Context Sensitive Solutions – A Guiebook for State DOTs. The National Academies Press, Washington, D.C.https://doi.org/10.17226/22063
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○ National Academies of Sciences, Engineering, and Medicine2007. NCHRP Project 3-68 Report: Guide to Effective Freeway Performance Measurement: Final Report and Guidebook. The National Academies Press, Washington, D.C.https://doi.org/10.17226/23196
15.
○ National Academies of Sciences, Engineering, and Medicine2020. NCHRP Project 03-122 Report (Phase 1): Performance-Based Management of Traffic Signals. The National Academies Press, Washington, D.C.https://doi.org/10.17226/25875
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○ National Academies of Sciences, Engineering, and Medicine2013. Guide to Incorporating Reliability Performance Measures into the Transportation Planning and Programming Processes. The National Academies Press, Washington, D.C. https://doi.org/10.17226/22595
17.
○ National Academies of Sciences, Engineering, and Medicine2013. Establishing Monitoring Programs for Travel Time Reliability. The National Academies Press, Washington, D.C. https://doi.org/10.17226/22612
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○ National Academies of Sciences, Engineering, and Medicine2014. Incorporating Reliability Performance Measures into the Transportation Planning and Programing Processes: Technical Reference. The National Academies Press, Washington, D.C.https://doi.org/10.17226/22594.
National Academies of Science, Engineering, and Medicine. Analytical Procedures for Determining the Impacts of Reliability Mitigation Strategies. The National Academies Press, Washington, D.C., 2012. https://doi.org/10.17226/22806
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US Department of Transportation, Federal Highway Administration (US DOT, FHWA). National Performance Measures for Congestion, Reliability, and Freight, and CMAQ Traffic Congestion, General Guidance and Step-by-Step Metric Calculation. FHWA HIF-18-040. https://www.fhwa.dot.gov/tpm/guidance/hif18040.pdf. Accessed July 28, 2020.
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DayC.LiH.CoxE.HortonD.BullockD.A Case Study on the Implementation of National Highway System Performance Measures Proposed in New Federal Rule Making. Presented at 96th Annual Meeting of the Transportation Research Board, Washington, D.C., 2017.
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BrennanT.RemiasS. M.ManiliL.Performance Measures to Characterize Corridor Travel Time Delay Based on Probe Vehicle Data. Transportation Research Record: Journal of the Transportation Research Board, 2015. 2526: 39–50. https://doi.org/10.3141/2526-05.
SadabadiK. F.PackM. L.IvanovN.JacobsT.Work Zone Performance Monitoring Application Development, Maryland State Highway Administration. MD-16-SHA-UM-3-16. 2017. https://rosap.ntl.bts.gov/view/dot/31406. Accessed July 28, 2020.
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KukkupalliV. M.PulugurthaS. S.Effect of Road Construction Projects on Travel Time Reliability. International Conference on Transportation and Development 2018, Pittsburgh, PA, 15–18 July 2018. https://doi.org/10.1061/9780784481547.005
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FontaineM. D.CottrellB. H.JrChunP.Considerations for the Development of Work Zone Mobility Performance Measures and Thresholds for Virginia Freeways. VCTIR 14-R6. February2014. http://www.virginiadot.org/vtrc/main/online_reports/pdf/14-r6.pdf. Accessed July 28, 2020.
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PestiG.BrydiaR.Work Zone Impact Assessement Methods and Applications. Transportation Research Record: Journal of the Transportation Research Board, 2017. 2617: 52–59. https://doi.org/10.3141/2617-07
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Highway Capacity Manual: A Guide for Multimodal Mobility Analysis, 6th ed. Transportation Research Board, Washington, D.C., 2016.
US Department of Transportation, Federal Highway Administration (US DOT, FHWA). Computation Procedure for Travel Time Based and Percent Non-Single Occupancy Vehicle (non-SOV) Travel Performance Measures. FHWA HIF-18-024. https://www.fhwa.dot.gov/tpm/guidance/hif18024.pdf. Accessed July 28, 2020.
