Abstract: A computer program product for speed limit enforcement is executable on a portable computer to measure the elapsed time it takes a motor vehicle to traverse a premeasured course along a roadway. The start and stop signals are manually input by a traffic officer via assigned keys on a keyboard, to capture the time interval between the last start signal and the stop signal. A start signal is entered upon a vehicle crossing a first measurement line, and a stop signal is entered upon the vehicle's crossing a second measurement line, the distance between the lines having been preselected from a set of geographic location data. The program converts the time measurement to the relevant units, typically miles per hour, for comparison to a threshold limit stored in a buffer. The time trial is displayed on the computer screen and each record is stored in a cumulative relational database for upload to a back office system for generating historical and statistical reports.