Electric car drivers in California may soon have a new perk: not paying tolls through 2015.

EVs and certain other zero-emission vehicles that run on hydrogen fuel cells and compressed natural gas are already eligible to drive in carpool lanes even when they only have one passenger, as long as they get a special sticker from the state. The program used to be even bigger, including hybrid cars like the Toyota Prius, but after successfully encouraging mass adoption of hybrids, that part of program expired. Now the state legislature is focused on encouraging consumers to buy even lower-emission cars.

Assembly Bill 2405, authored by Assemblyman Bob Blumenfield from Los Angeles, would allow every car that currently qualifies for carpool lanes to also avoid tolls. In some cases, the roads are both carpool and toll lanes, and in others, roads that are purely toll lanes would be affected. Critics in the government have argued that EV drivers should have to pay tolls, because the tolls are an important part of paying for some new roads.

Some have also argued that letting a single EV driver ride in a carpool lane actually encourages pollution, because the situation leads to more congestion on the road overall. That was a common argument made against allowing hybrid cars in carpool lanes, too. But a fascinating new study last year found that the opposite was actually true: When hybrid cars were banned from carpool lanes, congestion increased. The carpool lane became 15 percent slower. Researchers speculated that the reason was safety concerns — as regular lanes became more crowded, carpool drivers slowed to make passing in and out of the lane safer.

Just as carpool lane exemptions helped get hybrids on the road, the same can be done with electric cars. Exempting EVs from tolls is an extra push, and a good idea.

Main image: Model S by Tesla