Kilometers per hour (km/h) is a unit of speed that measures how many kilometers are traveled in one hour. It is commonly used to express the speed of vehicles, such as cars, bicycles, and trains. For example, if a car is traveling at 60 km/h, it means it can cover 60 kilometers in one hour. This measurement is part of the metric system, which is used in many countries around the world. Understanding km/h is important for road safety, as speed limits are often posted in this unit. It helps drivers gauge how fast they are going and ensures they adhere to traffic regulations.