Abstract: A device and a method for displaying to a person moving on a course the elapsed time between two points on the course. Generally, the person would be on or in a mode of transportation, such as a race car. A retroreflective switch is attached to the car and includes a transmitter and a receiver. The transmitter emits an infrared light beam such that the light beam strikes a reflector adjacent the course when the car is on the course adjacent the reflector. The receiver includes a light detector that outputs a detection signal in response to detecting the reflected light beam from the reflector. A processor connected to the receiver receives a first detection signal as the car is adjacent a first reflector and receives a second detection signal when the car is adjacent a second reflector and determines the elapsed time between said first and said second detected signals. A display connected to the processor receives the elapsed time and displays it to the person driving the vehicle.