Gas prices are a supreme motivator.

Drivers tend to convert to the fuel-efficiency religion once they get severely wounded in the wallet. It’s a sad fact that environmental concerns alone are often not enough… Of course, the best ways to save on gas costs are to walk, bike, and take transit (for an example of a city that has great sustainable transportation, check out Colombia’s Medellin). But if you’re going to drive, you should get the most fuel-efficient vehicle that meets your needs. Near the top of the list, the Chevrolet Volt and Toyota Prius can be found, and thanks to relatively high gas prices in the U.S. lately, they’ve both set new sales records in March 2012.

Prius sales were already up 52% in February compared to the previous year, and in March they broke new ground by going up 54% compared to last year, with 28,711 hybrids sold in the U.S.

The Volt also did very well, selling 2,289 units in March. It’s less than 10% of the Prius family’s numbers, but it’s still pretty good considering that the Prius has been around for over a decade and now has 3 models (with the bigger V and smaller C). It takes a while for people to become familiar with a new technology, but after a while people get used to seeing these new vehicles on the road and realize that they do the job just fine. The second and third generations of Volts should also help it broaden its appeal, as they’ll almost certainly be cheaper and have longer electric ranges.