Subcompact cars are often associated with being environmentally friendly, simple, and budget-friendly. One of the major advantages of these vehicles is their excellent fuel efficiency, which usually falls in the 30-40 miles per gallon range. Government organizations evaluate different models from manufacturers to give the public more information on fuel economy and other factors. The Environmental Protection Agency (EPA) has a unique approach when it comes to defining subcompact cars.
The Environmental Protection Agency (EPA) has its own method of categorizing vehicles, regardless of how a car manufacturer defines it. According to Federal Regulation Title 40—Protection of Environment, §600.315-08 “Classes of comparable automobiles”, vehicles are grouped by interior volume index, as follows:
- Minicompact – interior volume less than 85 cubic feet
- Subcompact – interior volume between 85 and 100 cubic feet
- Compact – interior volume between 100 and 110 cubic feet
- Midsize – interior volume between 110 and 120 cubic feet
- Large – interior volume more than 120 cubic feet
This system can lead to different classifications than those given by manufacturers, and can sometimes result in unexpected outcomes for subcompact cars with high fuel consumption.
It’s noteworthy to see the range of vehicles that fall within the subcompact class, as outlined in the chart. Interestingly, the model with the worst fuel efficiency was not a budget-friendly compact sedan with a small engine, but rather, the luxury Bentley Continental GT Speed. Despite its spacious 87 cubic feet of interior and 11 cubic feet of trunk space, it still qualifies as a subcompact according to EPA standards, making it a prime example of how size doesn’t always correlate with fuel efficiency. Despite its smaller size, it’s still more than enough for a day of shopping on Rodeo Drive.
The Environmental Protection Agency (EPA) compiles a list of vehicles with the best and worst fuel economy, using a metric called combined gas mileage. This calculation takes into account both city and highway driving, and when evaluating the Bentley Continental GT Speed, they found it to have a combined mileage of 15 mpg. This is less than half of the average fuel efficiency of 28 mpg for vehicles in 2023. However, this is not unexpected, as the GT Speed is powered by a massive 6.0-liter twin-turbocharged W12 engine, which provides a whopping 650 horsepower. Despite weighing over two tons, the GT Speed accelerates quickly, with Car and Driver estimating it can reach 60 mph in just 3.1 seconds.