The California Air Resources Board (CARB) voted on April 24, 2003, to modify its zero emission vehicle (ZEV) program, but will still require that automakers sell a certain number of ZEVs beginning in 2005. The revised program calls for automakers to sell a certain number of fuel cell vehicles -- rather than battery-electrics -- beginning in 2005 and allows for the production of gasoline-electric hybrid vehicles to fulfill part of the program's requirements. The biggest change to the program is a new compliance option that will require manufacturers to produce 250 fuel cell vehicles by 2008. The remainder of the requirements could be met with 4 percent production of AT PZEVs and 6 percent PZEVs. (See sidebar below for more information on ZEV Rule Vehicle Classifications.) The fuel cell requirement jumps to 2,500 from 2009-2011; 25,000 from 2012-2014; and 50,000 from 2015-2017. Automakers can subsititute battery-electric vehicles for up to half of their fuel cell mandates. Although the requirements do not take effect until 2005, manufacturers will receive credit for any ZEV, AT PZEV, and PZEV vehicles they sell in 2003 and 2004. ZEV Rule Vehicle ClassificationsZero Emission Vehicle (ZEV): A vehicle that essentially produces no emissions as it operates. Currently, this would include a pure battery electric (not a hybrid) or a hydrogen fuel cell vehicle. Advanced Technology Partial Zero Emission Vehicle (AT-PZEV): An AT-PZEV is a vehicle that uses some ZEV technology. Currently, there are no AT-PZEVs available to consumers. CARB expects certain gasoline/electric hybrid vehicles and natural gas vehicles will be certified in the AT-PZEV class. A plug-in hybrid could also qualify as an AT-PZEV. Partial Zero Emission Vehicle (PZEV): These are vehicles that have achieved the CARB's cleanest tailpipe emission standard -- the Super Ultra Low Emission Vehicle (SULEV) standard. They have nearly zero evaporative emissions and their emission control equipment is warranted for 15 years/150,000 miles.