A free program for Android, by Roberto Morini.

RaceTime is a FREE app to measure the speed and acceleration of your vehicle in km/h and mph. RaceTime is the most accurate speedometer app for your smartphone. The app is based on GPS speedometer, which uses the GPS sensor to measure the speed. The sensor provides more accurate results when it is used with a handheld device, as it is more sensitive to the environment.

The sensor works by measuring the distance between the smartphone and the vehicle. It works by calculating the speed of the vehicle based on the distance and the time.

To get more accurate results, it is recommended to use the RaceTime app with a sensor. To do so, connect the smartphone with the vehicle by placing it in the desired position. Once the vehicle is in motion, the RaceTime app will calculate the speed and acceleration.