The 2018 Mazda CX-5 powered by a 2.2-liter turbodiesel four-cylinder provides the same highway fuel economy as its gasoline counterpart, which may mute its appeal with potential buyers.

The diesel compact SUV, which has been in the works for several years, has been rated to deliver 31 mpg on the highway with front-wheel drive. It would deliver 28 mpg in city driving and 29 mpg combined, according to ratings released by the U.S. Environmental Protection Agency earlier this month. City fuel economy exceeds the gasoline-powered CX-5 by 3 mpg, and in combined driving, it would exceed it by 1 mpg.

The four-wheel-drive diesel CX-5 exceeds its gasoline counterpart by 3 mpg (27 mpg) in city driving, and matches it with 30 mpg on the highway. In combined driving, the diesel is 2 mpg better at 28 mpg.

The ratings would also put the diesel CX-5 at a disadvantage to its main competitor, the Chevrolet Equinox diesel, which achieved an EPA-rated fuel economy of 39 mpg in highway driving (front-wheel drive) and 38 mpg with an all-wheel drive system that can be switched off on some trim grades.