PL 54, Measuring Congestion and Travel Time Reliability for SHIFT 2026

Abstract PL 54, Measuring Congestion and Travel Time Reliability for SHIFT 2026 May 1, 2024 – June 30, 2025 KYTC uses the Strategic Highway Investment Formula for Tomorrow (SHIFT) to help project evaluation and prioritization. One of the components used for scoring projects is congestion. During SHIFT 2020, KYTC successfully transitioned from using volume-to-service flow ratio and design hourly volume to using vehicle hours of delay (VHD) as the congestion measure. The probe vehicle data in 2015-2017 were acquired and integrated with KYTC’s HIS network to calculate VHD for statewide network screening and project scoring. Since then, the biennial SHIFT process has been using probe speed data to measure congestion and travel time reliability. As KYTC starts to prepare for SHIFT 2026, more recent speed data are needed to update the congestion measure. The objective of the study is to assist KYTC in acquiring the 2022-2023 probe vehicle data, update the association between the third-party network and HIS links, update the congestion measure and the travel time reliability metric for SHIFT 2026. Major study components include: 1. Acquire 2022-2023 HERE speed data set for roadways in Kentucky. 2. Perform quality screening of the data set and produce statistics of temporal and spatial coverage. 3. Run the conflation process developed previously to link the HERE’s Streets network with KYTC’s HIS network and perform QA/QC to ensure conflation accuracy. 4. Calculate the congestion measure for statewide network segmented at around ¼ mile – to assist stakeholders identify congestion hot spots. 5. Calculate travel time reliability metric for statewide network segmented at around ¼ mile – to assist stakeholders identify unreliability hot spots.