There are three different classes being compact, mid-size, and full-size making up all of the SUVs on the streets and market. Through common knowledge, smaller and lighter vehicles get better gas mileage than heavier and bigger cars. In the case of a compact SUV, the Toyota RAV4, stands out of the bunch in getting an average of 22 city miles per gallon and 28 on the freeway.
While still a very clear winner, there are several runner ups that still get extremely close gas mileage in the Jeep Compass and Jeep Patriot. Next on the list is mid-size SUVs where it is a tight competition between two different models with the only difference being one extra mile to the gallon on the freeway. The winner in this contest is the Toyota Venza, with the Dodge Journey being only a few steps behind in being the best.
Lastly, the biggest class in comparison to the other two is the full-size SUVs. The reason for this is because there is a six-way tie between a variety of makes and models. All of these vehicles have an average of 17 miles per gallon city and 24 on the freeway. Since there is no first or second place, the list goes as follows: Buick Enclave, Chevrolet Traverse, Ford Flex, Ford Taurus X, GMC Acadia, and the Saturn Outlook.
Considering that there is no distinctive best for achieving the highest miles per gallon in the full-size SUV category, nobody is a winner and that means there is no way to determine which SUV is better than the other based on the gas mileage alone. However, if you are looking at all categories of SUVs then the winner would be the compact Toyota RAV4 that beats out all of the competition.