UC Davis Institute of Transportation Studies

Allowing single-occupant advanced clean vehicles to use carpool or high occupancy vehicle (HOV) lanes is an important non-monetary sales incentive. This incentive needs to be balanced against the potential cost of increased congestion on those lanes and reduced revenue of high occupancy toll (HOT) lanes, especially during peak travel periods. In a 2013 survey, when Plug-In in vehicle buyers were asked about their primary motivation to buy a plug in car, 57% of Plug-in Priuses, 34% of Volts and 38% of LEAFs identified the HOV sticker. Current legislation in California allows a limited number of stickers for plugin hybrid vehicles and an unlimited number for full battery electric vehicles. This paper offers an analysis on the impact of these stickers on the vehicle purchase decision and the resulting electric miles traveled. We also offer an analysis of the potential cost in terms of miles driven on HOV lanes. The results can help policy makers optimize the benefit for each additional permit while understanding the impact of different vehicle types.