The average fuel economy of light vehicles delivered in April matched the record set in March of 24.3 mpg (9.7 L/100 km) on the WardsAuto Fuel Economy Index, a 0.8% increase over year-ago and a 16% gain on the base rating established in fourth-quarter 2007.

(Note: The WardsAuto Fuel Economy Index was recalibrated this month with additional engine installation and sales information. The current and past scores referred to in this story and the accompanying table reflect those changes.)

The monthly score remained the same despite significant shifts in segment splits in the market, including a continued shift from cars to trucks.

Cars made up less than 50% of LV sales for the first time this year, accounting for 49.8% of deliveries, compared with nearly 51% last month. But the segment improved 0.3% month-to-month on the Index to 28 mpg (8.4 L/100 km) – a 2.1% improvement over year-ago, and a 15.7% increase over the base Index score set in Q4 2007.

The falloff in car market share came primarily as a result of midsize-model sales, which grabbed 20.9% of deliveries, the segment’s lowest share since December. However, sales within the segment tilted toward smaller, more-efficient vehicles, lifting the midsize-car FEI score 3.4% from March to 28 mpg (8.4 L/100 km) – a 2.7% bump over year-ago and a 13.8% improvement over the base period.

Light trucks equaled March’s record index rating of 20.3 mpg (11.6 L/100 km), despite a market shift toward traditionally less-efficient segments (pickups, vans, SUVs) and away from cross/utility vehicles. CUVs accounted for 24.6% of April’s LV sales, down from March’s 24.8% take, but offset any effect on the Industry FEI score by achieving a segment-record 22.4 mpg (10.5 L/100 km).

Mitsubishi regained the top spot among auto makers on the FEI, with a 28.3 mpg (8.3 L/100 km) rating, followed by Hyundai (27.5 mpg [8.6 L/100 km]), Toyota (27.4 mpg [8.6 L/100 km]) and Volkswagen (27.3 mpg [8.6 L/100 km]).

Ford broke the company record it set in February with a 23.9 mpg (9.8 L/100 km) rating, an 8.4% improvement over year-ago sparked by the introduction of several high-ranked alternative-power vehicles, and a 25.6% jump from the auto maker’s base-period rating.

Ford’s score helped lift the Detroit Three’s combined Index rating to a new high of 22.3 mpg (10.6 L/100 km), breaking the record set in March.

Nissan had its best month on the WardsAuto FEI as well, with a 26.3 mpg (8.9 L/100 km) score, a 6% boost over year-ago and 20.6% improvement over the auto maker’s base score.

Asia/Pacific auto makers had a collective Index rating of 26.5 mpg (8.9 L/100 km), down a hair from the region’s record FEI score set in April 2012, and a 14.9% improvement over the base period. European auto makers’ 23.1 mpg (10.2 L/100 km) score, meanwhile, was a 2% fall from year-ago (due largely to efficiency-leader VW’s drop in market share) but a 16% rise from the base period, directly in line with the overall industry improvement during the same period.

Light vehicles built in North America and sold in April achieved an April FEI score of 23.6 mpg (10 L/100 km), compared with the imported LVs’ score of 26.9 mpg (8.8 L/100 km).

Year-to-date, the WardsAuto Fuel Economy Index reached 24.3 mpg (9.7 L/100 km) up 0.8% from year-ago.

jsousanis@wardsauto.com