DIRT software uses your windows computer to measure your reaction time. It runs on Windows XP, Vista, 7, 8, and 10. It will measure your perception time; the time it takes for your brain to process the appearance of a red light. It will also measure your reaction time; the time it takes for you to react to the red light.Your PC's keyboard acts as your vehicle's accelerator and brake pedals. The Enter key serves as your accelerator pedal, and the Space Bar acts as your brake pedal.You can use DIRT to compete with your friends to find out who has the fastest reaction time. If you have an elderly friend or relative, you can check their reaction time to make sure that they can safely drive a vehicle. DIRT will also show you how far your vehicle will travel before you apply the brakes in feet and meters.