This study examined vehicle usage in plug-in electric vehicle (PEV) households throughout California through surveys, vehicle logging, and interviews between 2015-2018. A detailed survey covering vehicle purchase, vehicle fleet, driving and charging behavior, and sociodemographic information was completed by approximately 11,000 PEV owners. From these survey respondents, 272 households were recruited to participate in the vehicle data collection study, which consisted of installing a data logging device onto all household vehicles, including the non-PEVs. The logging study collected driving and refueling behavior on the order of 1 to 10 seconds per parameter for up to a year. From the logged households, 18 were selected to participate in interviews. At the vehicle-level, results indicate that the average percent electric vehicle miles traveled (eVMT), or percent of miles with no tailpipe emissions, in comparison to total vehicle miles traveled (VMT) for plug-in hybrid electric vehicles (PHEV) is 15-68 percent, depending on vehicle model.
However, the percent eVMT at the household-level for PHEVs studied was only 4-38 percent due to miles driven on household internal combustion engine vehicles (ICE). The percent eVMT on battery electric vehicles (BEV) at the vehicle-level is 100 12 percent (by definition), while at the household-level it ranged between 33-68 percent eVMT versus total household vehicle VMT.