A system, device, and corresponding method for enabling a user to
accurately control, monitor, and evaluate performance of a vehicle. A
portable programmable computer device that a user can readily install by
plugging it into a diagnostic connector port of the vehicle. The system
includes a detector for detecting the start time of first movement of the
vehicle independent of the on board diagnostic system. Velocity data from
the onboard diagnostic system is time stamped by a clock in the device
and stored. Velocity curves are generated from the velocity data and time
stamps. Wheel spin is accounted for by smoothing the velocity curve to
determine a point of inflection in the velocity indicative of termination
of wheel spin and creating correcting velocity and acceleration curves by
solving equations from the inflection point backwards on the curve down
to time zero. From the corrected curves, an accurate distance is
calculated.