Cars with all-wheel drive (AWD) provide superior traction on loose surfaces but there are downsides to the feature, particularly when it comes to fuel efficiency. The added weight of AWD causes your car’s engine to work harder and is more complex than 2WD models. Estimates suggest that cars with AWD engaged lose one or two mpg compared to 2WD versions, according to the Environmental Protection Agency. The drop in efficiency is even greater if you have a four-wheel drive car, which is heavier and even more complex. In 4WD cars, the drop in fuel economy can be as much as three mpg, when compared to 2WD models.
Source: Jalopnik
