With a more realistic plan for introducing zero-emission vehicles to its market, California earlier this month set a high but achievable standard for cleaner cars nationwide. Maine’s Board of Environmental Protection, expected to meet today, should continue this state’s practice of using the California standards for both low- and zero-emission vehicles.

Maine, like many neighboring states, uses California auto standards rather than the more relaxed federal standards to ensure that its clean-air regulations are effective but also based on a market large enough to provide real influence on the auto industry. New standards are needed now because while cars are dramatically cleaner than just a couple of decades ago, there are far more of them being driven far more miles than ever before. If Maine is to continue to make advances against air pollution, it should remain among the leaders in demanding lower-polluting cars.

The new low-emission vehicle (LEV) standard is based on levels of hydrocarbon emissions rather than the older nitrogen oxides standards. Both pollutants are major contributors to smog and either standard works as a measure, but California program sets more ambitious goals sooner and places light trucks, including SUVs, into the fleet average rather than earlier federal standards, which measured them separately. Given the 20-year decline in gas-mileage efficiency, setting tougher emissions standards is crucial.

And so is continuing with Maine’s commitment to promoting zero-emission vehicles (ZEV), which usually means battery-operated cars. The state’s Department of Environmental Protection wants to repeal Maine’s mandate for ZEVs on the reasonable grounds that the technology for them has not progressed as hoped. But California earlier this month, grappling with the same problem, came up with the solution of counting among the ZEV fleet gas-electric hybrids that have proved not only practical but popular. Honda and Toyota each make a version of these vehicles and several more manufacturers are expected to soon present their own. (It is worth the BEP noting, by the way, that the current “impractical” ZEV mandate contributed to spurring the auto industry to find a way to make these high-mileage hybrids work.)

The King administration has properly kept Maine in the lead of demanding clean-car technology, through the early LEV standards, the clean-fuel battles and, last year, the Cleaner Cars labeling program. In a time of national backsliding on fuel efficiency, the administration has shown foresight and perseverance.

With the more relaxed ZEV standards, there is no reason for the BEP to give up on these policies. It should hold the state to both the higher vehicle standards and it should do so with confidence that Maine will benefit from the decision down the road.