This app is all about driving at the correct speed.
The app gets your location and speed, and compares it to a vast database of speed limits on roads. It not only displays your speed and the speed limit for the current road, it can also warn you when you're driving too fast or too slow:
If you are driving slower than the set margin, the phone will vibrate shortly ever so often.
If you are driving too quickly, the phone will vibrate longer with the same interval.
You can customise the app in several ways, ranging from individually turning on and off the vibration warnings, to setting your car's deviation of the speedometer.
The app continues to run when the phone is locked.