Improved Quantification of High Occupancy Vehicle (HOV) Lane Delay Savings: Summary Report

High Occupancy vehicle (HOV) lanes are commonly evaluated using travel time studies. These studies are typically conducted infrequently and under non-incident conditions due to the cost and manpower required to conduct manual studies. A literature review did not identify any evaluations of HOV lanes under incident conditions. Due to the high occurrence of incidents in large urban areas where HOV lanes are more likely to be implemented, travel time studies conducted under non-incident conditions underestimate the true benefit of the HOV lanes. The prevalence of incidents is seen in Houston, where in 2003, an average of only 17 percent of morning peak periods and 10 percent of afternoon peak periods were found to be incident free on a given day on any of the four HOV corridors studied.