Consumer Information: " Why can't the Toyota Prius and Honda Insight get a carpool lane sticker?"

While the hybrid vehicles currently offered in California are very
clean vehicles, they do fall short of the EVs and alternative fuel vehicles
in several key areas and are not eligible for single occupant HOV lane
use. Even when counting power plant emissions, ZEVs offer significant reductions over hybrids and these emission rates improve over time due to the fact that hybrids produce more emissions as they age. In addition, gasoline powered vehicles have large emissions contributions due to the "upstream" pollution of refineries and fuel distribution.