The point of this app is not to 'follow' routes, but record them and compare them over certain sections (segments) to those recorded by others. Usually, 10 m is

The point of this app is not to 'follow' routes, but record them and compare them over certain sections (segments) to those recorded by others. Usually, 10 m is enough to figure out what road you're on, and after that they only look at the time it took to get from start to finish of the segment. Even if you're off by 10 m, at 20 mph that translates into about a second -- and these timings are pretty approximate anyway.