Push-to-pass is a mechanism on a race car which provides the driver with the ability to increase the car's power for short periods, usually via a button on the steering wheel. The system is designed to make overtaking easier, and hence make the sport more exciting to watch. The increased power can stem from various mechanisms, for example by changing engine modes or utilizing energy stored in an extra battery. Presently, all racing associations except drag racing ban nitrous oxide for use in boosting of internal combustion engines.