The average fuel economy of U.S. light vehicles sold in May was 25.5 mpg (9.2 L/100 km), the latest WardsAuto Fuel Economy Index indicates, the highest monthly outcome of this year but still 0.2% below like-2015.
The price per gallon of gasoline also hit a high point for the year, averaging $2.371 in May. Sales of alternative-power vehicles lost share from April, despite a 7% increase in the cost of fueling a standard gas-powered vehicle. May’s gas price was 15.4% below prior-year, marking a 4-month streak of double-digit declines.
Preference for light trucks over cars further hindered fuel-economy progress. Share of light trucks hit 58.4% of indexed sales, compared with 53.6% in prior-year.
Each vehicle type hit a record high rating as shoppers looked for relatively more efficient options within those categories. The index rating for cars reached 30.1 mpg (7.8 L/100 km), up 1.1% from May 2015, as shoppers chose smaller models. Light trucks achieved a 22.1 mpg (10.6 L/100 km) score, boosted 1.7% by higher sales of small CUVs and a small uptick in CUV plug-in hybrid variants.
General Motors was one of the few automakers to lose share of gas vehicles as diesel, electric, and plug-in models gained ground. This allowed the company to achieve its best-ever rating of 23.4 mpg (10.1 L/100 km) in May.
Honda scored a record 28.7 mpg (8.2 L/100 km), a 4.2% bump from year-ago, due to the Civic and Accord increasing the share of cars in its May sales mix.
Mazda was the highest-rated automaker (excluding electric-only Tesla) with a 30.2 mpg (7.8 L/100 km) result.
Ford (-5.5%), Mitsubishi (-5.3%) and Volkswagen (-5.1%) saw the greatest year-over-year declines. Ford was hurt by a strong gain in truck sales, even though diesel and PHEV sales were up slightly from last year. VW and Mitsubishi were hit by drops in the share smaller vehicles and alternative power.
For the first five months of this year, the WardsAuto FEI rating stood 0.1% below like-2015 at 25.4 mpg (9.3 L/100 km).
