Depending on where they live, electric-car owners can enjoy a variety of perks associated with the vehicle they drive.
That's especially true in California, which grants rebates for new plug-in car purchases, as well as access to carpool lanes for solo drivers in plug-in hybrids and electric cars.
And that latter benefit may be having an even greater impact on sales than previously thought, a new study says.
A study by UCLA's Luskin Center for Innovation found that carpool-lane access helped boost electric-car sales in four major California metropolitan areas.
The study is the first to look specifically at the effect of carpool-lane access on sales, according to The Los Angeles Times.
Researchers looked at sales data from Los Angeles, Sacramento, San Diego, and San Francisco, and found that solo carpool-lane access prompted the purchase of more than 24,000 plug-in electric cars and hybrids between 2010 and 2013.
I-95/395 reversible HOV lanes, located in the middle of the freeway (pic by Mariordo at Wikimedia)
That's about 40 percent of sales for such vehicles, the study says.
Researchers looked at more than 7,000 of California's 8,057 census tracts. They looked at the number of plug-in car sales and the mileage of carpool lanes within a 30-mile radius of each census tract.
They concluded that granting access to 20, 40, and 140 miles of carpool lanes accounted for two, four, and 10 additional sales per census tract, respectively.
ALSO SEE: California Extends Electric-Car HOV Lane Access To 2019 (Sep 2013)
The study was funded by the California Air Resources Board, which manages the carpool-lane access program.
Currently, green and white stickers give plug-in hybrids and electric cars, respectively, access to carpool lanes without passengers onboard.
There are an unlimited number of white stickers available for "zero-emission vehicles," including battery-electric cars, hydrogen fuel-cell cars, and vehicles powered by compressed natural gas (CNG).
Green HOV-Lane Sticker
The total number of green stickers was originally capped at 40,000, but the limit was raised multiple times--to the current limit of 85,000.
As of November 17, the California Department of Vehicles has issued 80,876 green stickers.
Yellow stickers that gave hybrid vehicles solo carpool-lane access expired June 30, 2011.
The carpool-lane exemption was originally set to expire this year, but legislation passed in late 2013 extended it to 2019.
When the time comes to renew it again, research like the UCLA study could be a valuable tool for convincing legislators to continue granting this perk to electric-car drivers.