A free program for Android, by Gunnar Daehling.

This app is designed for drivers who want to keep track of the speed of their vehicle in real-time. With this app, you can easily avoid speed-related incidents by setting up your own speed signs at home on the map. It also includes a GPS speedometer that can be used to calculate the speed of your car in kilometers per hour and miles per hour. 

This app is a great addition to other navigational maps because it can be shown overlayed on top of other apps. The real-time data is provided by OpenStreetMap (OSM) and you can also make direct edits in the private Database from TempoMaster.