Project Summary
The state of California has a vast network of close to 1,750 lane miles of managed lanes. This accounts for nearly 40% of the total managed lane network in the US. A managed lane facility includes High Occupancy Vehicle lanes (HOV), High Occupancy Toll lane (HOT) and Express lanes. Congestion on HOV lanes in California has been increasing over the years, with as much as 68% of total lane miles found to meet Federal standards for HOV lane degradation. As per Federal definition, an HOV facility is degraded if vehicles operating on the facility fail to maintain a minimum average operating speed (45 mph) 90% of the time over a consecutive 180-day period during morning or evening weekday peak hour periods. Caltrans have been preparing annual degradation action plans to outline measures to mitigate degradation. Despite improvements in certain corridors, the number of degraded lane miles continue to increase. Prior research has shown limitations of ‘one-dimensional’ definition for HOV lane degradation, which as an aggregate measure provides very little information to practitioners. A more nuanced approach is helpful; one that considers a variety of factors such as comparative advantage over adjacent general purpose lanes, travel time reliability, HOV access type, geometry, incidents, and demand patterns. The main objective of this project is to develop analysis and modeling methods to help in policy decisions on managed lanes, with specific focus on HOV lanes, including the performance and degradation these lanes as well as the enforcement of lane utilization rules and their violation. The second objective is to apply these methods to evaluate the effectiveness of incentive policies allowing clean air vehicles to travel in HOV lanes. The third objective is to provide new tools, including simulation techniques, for decision-making with regard to conversion of HOV lanes to HOT lanes.