Electric and plug-in hybrid vehicle drivers in California who now use the carpool lane may get those privileges revoked next year.

Thanks to a federal transportation bill, the green cars are able to apply for a Clean Air Vehicle decal through the state to use the special lanes, allowing them to bypass some traffic snarls during busy commuting times.

But unless the federal legislation is renewed, those privileges will be canceled Sept. 30, 2025.

The federal Fixing America’s Surface Transportation Act (FAST Act) authorizes carpool lanes, also known as high-occupancy vehicle lanes, in 20 states. The lanes require vehicles to have a minimum number of occupants during peak traffic hours.

But in California, the state’s carpool lane requirements allow single-occupant drivers of fuel-efficient low-emission vehicles to use them.

“Congress must first act before California could extend the program,” Ronald Ongtoaboc, a spokesperson for the California Department of Motor Vehicles, said in a statement to SFGATE, a news site based in San Francisco.

Any extension to the program must also be approved by the state Legislature.

Currently, there are 411,133 vehicles in California with active Clean Air Vehicle decals, according to the Department of Motor Vehicles.