The WardsAuto Fuel Economy Index indicates the average fuel economy of light vehicles sold in the U.S. in March rose to an all-time high of 25.4 mpg (9.3 L/100 km), up 1.1% over year-ago and 21.2% above the base index score set in fourth-quarter 2007.

The national average gasoline price was $2.546 per gallon in March, 29.4% below same-month 2014. Although prices have been at 6-year lows this year, consumers dealt with a 10.6% increase from the prior month, the biggest month-to-month increase in four years.

Market share typically shifts to cars and away from light trucks from February to March, but this year’s shift was the greatest since 2011.

Cars averaged 29.2 mpg (8.1 L/100 km) on the index, 0.6% better than last year, but still behind the record-high of 29.5 mpg (8.0 L/100 km) last seen in August 2014. Midsize cars were the only segment to score lower than last year, down just 0.8%.

Light trucks hit a record 21.8 mpg (10.8 L/100 km), shooting up 3.6% from last year. Domestically built light trucks improved 4.8%, while the average for imported models dropped 1.2%.

CUVS, the highest-rated light-truck segment, scored an all-time high of 23.9 mpg (9.9 L/100 km) and gained market share. Vans also hit a record high in March at 21.6 mpg (10.9 L/100 km).

Despite a drop in sales of alternative powertrains from February, Honda hit an all-time high of 27.5 mpg (8.6 L/100 km) as shoppers looked to the automaker’s smaller, lighter models.

Conversely, Volkswagen buyers turned away from small cars in March, but showed greater interest in diesel and electric powertrains. The company reached a peak score of 29.5 mpg (8.0 L/100 km).

The other automaker nearing the 30 mpg (7.8 L/100 km) benchmark, Mazda, hit a record 29.4 mpg (8.0L/100 km) last month.

For the first three months of this year, the index rating sat at 25.3 mpg (9.3 L/100 km), 1.3% above the same period in 2014.