WASHINGTON (AP) — New government data shows gas mileage for 2016 model year light-duty vehicles sold in the United States made smaller than expected gains in fuel economy over the last year, though new cars are generally sipping less gas and spewing less planet-warming carbon emissions than their predecessors.

The Environmental Protection Agency released its latest annual CO2 fuel economy trends Thursday, showing 2016 vehicle fuel economy was 24.7 miles per gallon, higher than model year 2015 by only one-tenth of a gallon. That was well below the projected gain of 1 mpg. Carbon from vehicle ta...