Photo by Simon Forsyth via Flickr

The Obama administration announced earlier this week that the National Highway Traffic Safety Administration and the Environmental Protection Agency are working toward a fuel economy fleet-average standard of 56.2 miles per gallon by 2025. Fuel economy standards for the 2012 model year are at 29.7 miles per gallon, and will have to reach 34.1 MPG by 2016.

This significantly higher fuel economy standard suggests Americans will be driving much different vehicles in 14 years. We’ll probably see more hybrid models, and, although cars continue to get larger and heavier, possibly a return to smaller, lighter vehicles. The requirement to make cars more efficient has some wondering if it will also make cars more expensive.

Senator Carl Levin (D-Michigan) who represents Detroit, probed the Obama administration on how it arrived at such a number. As it turns out, 56.2 MPG is based on five percent annual increases in fuel efficiency, so if you take the 34.1 MPG requirement that goes into effect in 2016, and work your way up from there, well, you do the math.

An average fuel economy of 56.2, while ambitious by today’s standards, is actually lower than the 60 MPG average the Obama administration had originally proposed. Negotiations are still underway with American automakers, so this number could change. An official number isn’t expected until September.