The average fuel economy of light vehicles delivered in March climbed to a new high of 24.2 mpg (9.7 L/100 km) on the WardsAuto Fuel Economy Index, a 0.5% increase over year-ago and a 15.1% gain on the base rating established in fourth-quarter 2007.

March was the third consecutive month in which the industry broke the previous Index record.

The benchmark FEI score was achieved in the face of strong sales of vehicles in the less-efficient segments: pickups (16.7 mpg [14.1 L/100 km]), SUVs (17.6 mpg [13.4 L/100 km]) and Large CUVs (19.4 mpg [12.1 L/100 km]).

However, Light Trucks collectively achieved a record 20.2 mpg (11.6 L/100 km) rating on the index, with the help of best-ever scores in three light-truck segments, including a 25.3 mpg (9.3 L/100 km) rating for Small CUVs.

Cars scored 27.6 mpg (8.5 L/100 km) for the third straight month.

After ceding the top position to Mitsubishi in January and February, Toyota led all auto makers on the March FEI with a 27.4 mpg (8.6 L/100 km) rating, down slightly from prior-month and well below the high-water mark of 28.7 mpg (8.2 L/100 km) the auto maker set in January 2010.

Volkswagen’s 27 mpg (8.7 L/100 km) score was next-best, followed by Kia’s 26.2 mpg (9.0 L/100 km) – both scores were the auto makers’ second-best efficiency ratings to date.

The index was helped by upward movement across the segments. Nissan recorded its highest volume sales and its best FEI score of 25.9 mpg (9.1 L/100 km) in March, on the strength of the market’s best-selling car, the Altima midsize sedan (25.8 mpg [9.1 L/100 km]).

Subaru’s best-ever 23.2 mpg (10.1 L/100 km) score was aided by record sales of its two most fuel-efficient vehicles, the BRZ small car (27.3 mpg [8.6 L/100 km]) and XV Crosstrek CUV (26 mpg [9.0 L/100 km]).

While Jaguar Land Rover’s lineup of large luxury cars and SUVs anchored the auto maker to the bottom of the index, the brands still achieved a combined best of 17.3 mpg (13.6 L/100 km), buoyed by strong sales of the Evoque midsize CUV (23.5 mpg [10.2 L/100 km]).

Chrysler at 20.4 mpg (11.5 L/100 km) and General Motors at 21.9 mpg (10.8 L/100 km) individually recorded their second-best monthly scores on the index, while Ford – boosted in part by its expanding lineup of hybrid and electric vehicles – tied its best score of 23.9 mpg (9.9 L/100 km), established in February.

Collectively, the Detroit Three set a new FEI record of 22.1 mpg (10.6 L/100 km), a 3.3% improvement over year-ago and a 15.3% increase over their base-period score.

Year-to-date, the WardsAuto Fuel Economy Index sits at 24.1 mpg (9.8 L/100 km), up 1.2% from year-ago and 15.1% better than the index base score of 20.9 mpg (11.2 L/100 km).

jsousanis@wardsauto.com