Average sales-weighted fuel-economy rating (window sticker) of purchased new vehicles for October 2007 through January 2013

Average new-car fuel economy figures ended two straight months of in January and reached an all-time record of 24.5 miles per gallon, the University of Michigan Transportation Research Institute (UMTRI) says.

Once again, Americans appeared to respond to higher gas prices by buying more smaller-engined cars, hybrids and plug-in vehicles. Average US gas prices rose about 20 cents a gallon last month to about $3.50 a gallon, the highest average since mid-October, according to the AAA.

As a result, January's MPG average marked about a half-mile per gallon increase from December and about a nine-percent increase from year-earlier MPG numbers. Last month, UMTRI said 2012 marked a record year for new-vehicle fuel economy, which averaged 23.8 mpg. You can read all of UMTRI's report and check out our full report on January's advanced-powertrain vehicle sales here.