Sales of General Motors' Chevrolet Volt plug-in car, which had been dwindling in recent months, are enjoying a big resurgence in California, a state with some of the highest gas prices in the nation.
But the uptick in Volt sales isn't about saving gas, it's more about saving time.
Despite being incredibly fuel efficient, the Volt's emissions when operating on gasoline weren't clean enough to qualify it to drive in California's car-pools lanes, relegating Volt owners to the whims of grueling California traffic.
But now, thanks to some new engineering tweaks to fix that issue, 2012 model year Volts sold in California can drive in those free-flowing HOV (high occupancy vehicle) lanes -- even with only one person in the car.
For GM, winning access to those lanes has been like striking gold.
Rollercoaster sales: Interest in the Volt had declined in California prior to the availability of cars with the new emissions package, according to data from Edmunds.com.
The Volt first went into production at the very end of 2010. When first offered, California's sales accounted for about half of all U.S. sales. But by the end of that year, they fell to just 9% of U.S. sales.
Once the emissions tweaks for the 2012 model were made, California sales bounced back. By February and March they grew to 39% of all U.S. sales.
GM has sold about 7,000 Volts in the U.S. so far this year.
The sales pattern indicates Californians held off buying the cars, waiting for the ones with HOV access to arrive at dealerships, said John O'Dell, a "green cars" analyst with the automotive Web site Edmunds.com.