The average U.S. drivers stays within the speed limit range on most urban and rural interstate highways, according to data collected using TomTom's map business unit Tele Atlas.

Using Speed Profiles, the historical speed database, TomTom was able to aggregate, anonymously, the actual speeds that millions of GPS-enabled drivers have traveled over the last two years.

According to TomTom's findings, the fastest road, "America's Autobahn," is on Interstate 15 in Utah and Nevada, with speeds averaging 77.67 miles per hour. Many of the states with the fastest highways are in the middle part of the country. The average speeds on roads in Mississippi, Nebraska, Kansas, Iowa, Idaho, Alabama and Missouri exceed 67 miles per hour.

Meanwhile, the slowest roads can be found in Washington, D.C., where speeds average 46 miles per hour. Following Washington, D.C., the states with the slowest interstates are Hawaii, Delaware, Rhode Island and Oregon.

Speeds on single interstate highways that span a number of states, such as the I-95 route running from northern Maine to southern Florida, differ dramatically depending on where you are. Along that highway, the fastest section is in South Carolina; the slowest sections are in Virginia, New York, New Jersey and Connecticut.