GPS Overestimates Distance Traveled

This is interesting: GPS units will systematically overestimate distance travelled (by as much as 2%), according to researchers from Salzburg and Delft. See this IEEE Spectrum article for details, or this paper. Systematic bias in measurement error is the cause. This issue has relevance to long road races like the World Solar Challenge, if teams are using a GPS unit to calculate distance travelled – they may not be as close to the finish line as they think!