- Use a stopwatch and a long, straight roadway to measure the time it takes the RC car to travel a known distance. Divide the distance by the time, convert to miles per hour, and you have the approximate speed.
- Install a built-in speedometer on your RC car. This may require modifying the car, so check with the car's manual or manufacturer before proceeding.
- Use a GPS tracker. Some GPS devices are designed to be conveniently mounted on RC cars, and can calculate speed and distance traveled.
- Use a laser speed gun. Laser speed guns are available at many sporting goods and home improvement stores, and can be used to measure the speed of moving objects from a distance.
