The United States Environmental Protection Agency (EPA) and Department of Energy (DOE) released their annual Fuel Economy Guide for 2018. Vehicles from Hyundai, Chevrolet, BMW, and Volvo rank among the most fuel-efficient cars in their respective classes.

The EPA and DOE found that fuel economy leaders among their respective classes included the Hyundai Ioniq Electric (mid-size cars), Hyundai Ioniq Blue and BMW 740e xDrive (large cars), Chevrolet Bolt EV (small station wagons), and Volvo V90 FWD (mid-size station wagons).

Excluding battery-electric vehicles, the Toyota Prius Eco joins the Hyundai Ioniq Electric as best-in-class for fuel economy among mid-size cars.

Luxury cars from manufacturers such as Rolls-Royce, Ferrari, and Bentley rank among the least efficient vehicles by EPA size class. The EPA also ranked the Volvo V60 Polestar AWD and Mercedes-Benz AMG E63 S 4matic as the least fuel efficient small and mid-size station wagons, respectively.

The EPA and DOE determine fuel economy rankings based on combined city and highway fuel economy estimates, with city and highway consisting of 55% and 45% of driving, respectively.

The guide also includes additional information on diesel, compressed natural gas, fuel cell, battery-electric, hybrid, and ethanol-flexible fuel vehicles.

The Fuel Economy Guide provides annual fuel cost estimates for each vehicle, which are based on assumptions that a vehicle will travel 15,000 miles per year with cost-per-gallon assumptions for fuel. Greenhouse gas ratings are also listed with each vehicle.

Click to see the 2018 Fuel Economy Guide.