A GPS timer to measure the acceleration time of your vehicle in miles per second(MPH), or in kilometers per hour(KMH). Weather you have a car, a bike, a motorcycle it doesn't matter.
How it works:
Simply put your device somewhere in the car, open the app(don't forget to choose your desired speed units, KMH or MPH, via the settings menu), wait for a valid GPS fix and go. The app will automatically detect when the vehicle has started accelerating and start the timer. Once it reaches 60 mph, or 100 kmh, the timer will stop and will reset as soon as you stop the car for a new try run.