What if gasoline and diesel cars and light trucks were simply eliminated altogether from the new vehicles sold in a state?
Residents of one state in the U.S. may, eventually, find out.
California already leads the nation in promoting zero-emission vehicles, but the Golden State may soon take that policy a step further.
DON'T MISS: Will California lead the green-car resistance? (Dec 2016)
Speaking at the annual VerdeXchange conference in Los Angeles, Mary Nichols, chair of the powerful California Air Resources Board, said the state is now pursuing a goal of 100 percent zero-emission light-duty vehicles, according to advocacy group Plug-In America.
California already enforces stricter emissions standards than the rest of the nation, as well as a zero-emission vehicle mandate that requires automakers that reach certain sales volumes to sell battery-electric or hydrogen fuel-cell vehicles.
It is also the only state where hydrogen fuel-cell cars are currently sold, because it alone has the fueling infrastructure to support them.
California Air Resources Board chair Mary Nichols (via Twitter)
CARB chair Nichols' declaration is likely welcome news to electric-car advocates amid uncertainty about the direction of federal environmental policy.
It is expected that the Trump administration's environmental policies will be radically different from those of the Obama administration.
As a candidate, President Trump promised to "bring back coal," and generally support the fossil-fuel industry.
He appointed climate-science deniers to lead the Environmental Protection Agency and Energy Department, and tapped former ExxonMobil CEO Rex Tillerson for the post of secretary of state.
California officials have already indicated that they plan to lead the "resistance" against any Trump policies that roll back commitments to reducing carbon emissions.
Other governmental bodies outside the U.S. have proposed eliminating or curtailing the sale of internal-combustion vehicles.
2015 Hyundai Tucson Fuel Cell, 2016 Toyota Mirai at hydrogen fueling station, Fountain Valley, CA
Last October, the the German Federal Council adopted a bipartisan measure that would ban the sale of new vehicles with internal-combustion engines in the country after 2030.
Prior to that, the Dutch parliament passed a motion to end sales of new gasoline and diesel cars by 2025.
In August 2015, Norwegian government officials began discussing the adoption of a similar goal.
And it's not just European countries, either.
India has proposed not just ending sales of new internal-combustion cars, but converting the nation's entire fleet to electric power by 2030.
Last year, Indian Power Minister Piyush Goyal proposed an incentive program that would enable this ambitious goal by making electric cars extremely cheap.