High-Occupancy Vehicle Lane Performance Monitoring and Improvement in California

A high-occupancy vehicle (HOV) lane, by design, is intended to live up to a higher performance standard for vehicles with a required number of occupants. When exempt vehicles are permitted to access HOV facilities, such as through a clean air or toll-paying vehicle program in California, the facilities must be monitored for degradation. If degraded, remediation actions must be taken to remove degradation per Title 23 of the United States Code, Section 166. A degraded facility is defined as one that does not meet the minimum average operating speed of 45 mph for 90% of the time over a 180-day monitoring period during morning and evening weekday peak hours (or both), in the case of an HOV facility with a speed limit of 50 mph or greater. In this paper, the HOV lane performance monitoring and improvement program in California is presented, including occupancy violation monitoring, HOV lane effectiveness assessment, an annual degradation report, and an annual degradation mitigation action plan. The specificities of the degradation monitoring and reporting, causational investigation and analysis, degradation mitigation strategies, and project delivery challenges are also discussed. The 2023 degradation monitoring reports showed that 21% and 34% of the monitored HOV lane miles were degraded for the morning and evening peak periods, respectively. Statewide occupancy violation rates are lower during the evening peak periods than in the morning peak periods. Efforts are ramping up across the state to mitigate the degraded HOV lane miles.