Operational Effect of Single-Occupant Hybrid Vehicles in High-Occupancy Vehicle Lanes

Abstract

In an effort to reduce the environmental impact of automobile travel, legislatures across the country are considering laws that would allow single-occupant hybrid vehicles to use high-occupancy vehicle (HOV) lanes. In time, single-occupant hybrid vehicles could increase congestion in HOV lanes such that the travel time incentive would be lost. A microscopic simulation method is presented; it examines the possible effects of a proposed California state hybrid HOV law that would allow single-occupant hybrid vehicles into the state's HOV network. The results from a 12-by-16-mi freeway network being simulated around Irvine, California, under several travel demand scenarios show that the policy would not have a significant effect on HOV lane operations in the study area. Although the addition of single-occupant hybrids may have only a modest impact on short-run HOV lane operations, policy implementation opens the door to more difficult long-term policy questions.