General Motors has announced that a new low-emissions version of its 2012 Chevrolet Volt plug-in hybrid car has been cleared to use California's 1,400 miles of carpool lanes. While that could help Volt drivers spend less time on notoriously crowded Los Angeles freeways, it could also put more money in car owners' pockets.

According to GM, the Low Emissions Package—standard on all California-bound Volts—makes the extended-range hybrd eligible for up to $1,500 in rebates from the state's Clean Vehicle Rebate Project. Coupled with the federal tax credit for green vehicles, California car shoppers could shave about $9,000 from the Volt's base price of $39,995—in addition to the $1,005 price cut by GM announced when the hybrid car rolled out nationwide last June.

Like other plug-in hybrid cars, the improved Volt could also help drivers save money on gas—which, on average, has gone up by about 11-cents per gallon in California just this past week.

In our experience, the Volt usually allows you to drive gas-free for 35 miles; that exact number depends on weather and driving style. When the battery is depleted, a backup gasoline engine will kick in to keep the electric motor running and allow you to keep driving for up to 315 more miles before refueling. If you charge every night and your daily drive fits within the battery's range, you might never need to buy gasoline.

Running on electricity alone, the Volt costs about 4 cents per mile at national-average electric rates—much less than it would take to fuel any gas-powered car. But your actual cost will depend on your electric rates, which vary greatly from state to state.

Still, there some compromises with the Volt, such as visibility, controls, and passenger space. Read our full Chevrolet Volt road test.

For more information about buying green, fuel-efficient vehicles, see Consumer Reports Guide to alternative energy.