California Partners for Advanced Transportation Technology

The two most common types of high occupancy vehicle (HOV) lanes in California are continuous access, prevalent in Northern California, and buffer-separated limited access, prevalent in Southern California. This report describes the evaluation of operational performance of HOV facilities in several regions in California with different access types as well as a before-after comparative study of California facilities where access types were converted in recent years. A set of performance measures were defined and selected to indicate how well the HOV facilities achieve intended goals – congestion relief, travel time saving, greater highway capacity. Additionally, an alternative methodology of indicating how well the operations perform in terms of the traffic flow fundamental diagrams was also adopted.