1. A method for calculating the point at which a vehicle has traveled a selected distance from a standing start point, wherein the distance calculation corrects for errors in the velocity data available from the vehicle's onboard diagnostics system, comprising the steps of: accessing the onboard diagnostic system for receiving said vehicle velocity data; detecting the start time of said vehicle travel using a detector that senses movement of said vehicle, wherein said detector is independent of said onboard diagnostic system; generating a first set of velocity values based on data acquired by said detector; storing said first set of velocity values; storing a second set of velocity values based on the vehicle velocity data received from said onboard diagnostic system; generating a time stamp for each of said velocity values of said first set and said second set; generating corrected velocity values as a function of said first set and said second set of velocity values, said time stamps, and said detected start time; and integrating said corrected velocity values to calculate the point at which the vehicle has traveled the selected distance from said standing start point.