California Partners for Advanced Transportation Technology

This study evaluates the operational and network-level impacts of changes to High-Occupancy Vehicle (HOV) and High-Occupancy Toll (HOT) lane eligibility policies along a 15-mile segment of Interstate 210 (I-210) in Los Angeles County. Using a calibrated microsimulation model in Aimsun Next, the research examined both supply-side and demand-side strategies to assess their influence on corridor travel times, Vehicle Miles Traveled (VMT), Vehicle Hours Traveled (VHT), and overall network performance.

Supply-side scenarios evaluated the effects of restricting lane eligibility to HOV3+ or higher, converting existing HOV2+ lanes to HOT2+ lanes with dynamic tolling, adding new HOT lanes, and converting general-purpose lanes to HOT lanes. Results indicate that tightening eligibility improves HOV lane performance but leads to excessive queuing and unmet demand. Conversion to HOT2+ with dynamic tolling improves efficiency only when tolling operations are properly managed. Adding HOT capacity yields the greatest systemwide benefit, while converting a general-purpose lane to HOT capacity reduces throughput.

Demand-side scenarios assessed increased vehicle occupancy, higher traffic demand, and variations in travelers’ value of time. Behavioral changes alone were found insufficient to offset congestion impacts without structural improvements or major shifts in travel behavior.

The study concludes that combining supply-side enhancements—such as lane additions and optimized tolling—with moderate demand management provides the most effective and sustainable strategy to reduce congestion, improve reliability, and support Senate Bill 743 (SB 743) objectives for corridor efficiency.