Bach-Simpson's™ Doppler Speed Sensor is a reliable and field service proven system with no moving parts. With no connection to the vehicle axle, there is no need for wheel size adjustments to produce a true ground speed signal. The sensor is mounted and wired independently from the truck to simplify routine truck maintenance tasks. Its ease of application and operational features make this speed sensing system second to none. The sensor is mounted under the vehicle and determines the vehicle speed via a low power microwave signal. This signal is processed to provide an accurate, true ground speed reading. The Doppler Speed Sensor's output is compatible with existing speed indicators and event recorders, making it part of a cost effective system.