Abstract:In November 1998, the California Air Resources Board modified its Zero Emission Vehicle (ZEV) "mandate" so as to allow certain vehicles with measurable tailpipe emissions to earn partial credit toward the 10% requirement scheduled for 2003 and beyond. This change in the ZEV mandate provides automakers with a greater incentive to market a broad range of very low-emitting vehicles, and reduces the requirement for 'pure' zero-emission vehicles. Partial ZEV credits will be given to vehicles that have very low tailpipe emissions, all-electric driving capability, integrated advanced componentry, and use inherently clean fuels. Even very clean-burning gasoline vehicles can earn partial ZEV credit. This report describes the methods and conditions for granting partial ZEV credits, examines credit allocations to particular technology and fuel options, and explores the implications of the proposed changes. This report is an update of UCD-ITS-RR-98-5.