Programmable road speed limiter that allows the installer or end-user to program a maximum vehicle speed anywhere from 10 mph to 80 mph. Why do I need to eliminate speeding? Every 5 mph over 60 reduces fuel economy by approximately 7% and speeding nearly triples your chances for an accident. Speed Sentinel does not limit engine output below the maximum speed. Other features include a passing mode, override mode, and a forced idle mode. Forced idle allows a hidden switch to deactivate the throttle pedal when the driver is not in the vehicle. This could reduce vehicle thefts.