Americans are driving well below the speed limit on average, according to new data by Tele Atlas, the mapping unit of sat-nav maker TomTom.
Using data collected anonymously from millions of GPS systems in use on US roads, it discovered that average speeds don't top 70mph in any US state.
The fastest stretch of motorway in the US is the I-15, which runs from Utah to Nevada. The average speed of vehicles tracked on this road was 77.67mph, even though the speed limit is 80mph in places.
The area where drivers are most likely to push the limits is Mississippi, but even then the average speed was 70mph - exactly the motorway limit.
The slowest drivers came from the District of Columbia, where motorway drivers average just 46mph.