SANTA MONICA, Calif. — Four years ago, TrueCar’s TrueMPG, which measures monthly fuel economy averages by brand, manufacturer, origin and vehicle segments using Environmental Protection Agency (EPA) ratings, stood at 20.3. Last year, it rose to 22 mpg. Last month, actual fuel economy increased to 23.4 mpg.

“Gas prices are nearing $4 per gallon nationwide and consumers are getting reluctant to pay any additional money at the pump when buying a new vehicle,” said Jesse Toprak, vice president of market intelligence at TrueCar.com. “Consumer buying behavior has shifted and vehicles today are more fuel-efficient than ever, contributing to significant gains in fuel economy of over three miles per gallon since 2008.”

According to TrueCar.com, the TrueMPGTM for vehicles sold by U.S. manufacturers averaged 21.3 mpg in March 2012, up from 20.5 mpg in March 2011. European manufacturers increased their average fuel economy for vehicles sold from 20.5 mpg to 22.7 mpg, while Japanese manufacturers increased their average fuel economy from 23.6 MPG to 25.0 MPG. South Korean manufacturers increased their average fuel economy for vehicles from 26.0 MPG to 28.1 MPG.