Hyundai's 40-MPG Elantra Eco Starts at $20,650

Hyundai most fuel-efficient Elantra compact car, the 2017 Elantra Eco, retails for at least $21,485 and offers the first Elantra model that provides an EPA-rated 40 mpg for highway driving.

The 2017 Elantra Eco also provides 35 mpg in combined city and highway driving, as well as 32 mpg in city driving. The vehcile's highway fuel economy offers a more than 5% improvement over a comporable 2016 Elantra.

The Elantra Eco is equipped with a 1.4L turbo GDI four-cylinder. This engine produces 128 hp at 5,500 rpm and 156 lb.-ft. of torque. It will be mated to an EcoShift 7-speed dual-clutch transmission.

The most fuel efficient 2016 Elantra provided 38 mpg in highway driving.