A spoiler is an automotive aeroynamic device whose intended design function is to 'spoil' unfavorable air movement across a body of a vehicle in motion. This can result in improved vehicle stability by decreasing lift, which may cause unpredictable handling in a car at high speeds. Spoilers are often fitted to race and high-performance sports cars, although they have become common on passenger vehicles, as well. Some spoilers are added to cars primarily for styling purposes and have either little aerodynamic benefit or even make the aerodynamics worse.