A speed meter, also known as a speedometer, is a device used to measure the speed of a vehicle. It provides real-time information about how fast the vehicle is traveling, typically displayed in miles per hour (mph) or kilometers per hour (km/h). Speed meters are essential for drivers to maintain safe speeds and comply with traffic laws. Speed meters can be found in various vehicles, including cars, motorcycles, and bicycles. They often work by measuring the rotation of the wheels or using GPS technology to calculate speed. Accurate speed measurement is crucial for road safety and helps prevent accidents caused by speeding.