What device is commonly used to measure your speed on the road?

The commonly used device to measure your speed on the road is the speedometer. This instrument is an essential part of any vehicle's dashboard, providing real-time information about how fast the vehicle is traveling. Speedometers typically work by interpreting data from the vehicle's transmission and wheels, displaying the speed in either kilometers per hour (km/h) or miles per hour (mph).

In contrast, other devices serve different purposes: the tachometer measures engine RPM (revolutions per minute), helping drivers understand engine performance rather than speed. The odometer tracks the total distance the vehicle has traveled over its lifetime, giving insight into mileage but not current speed. An altimeter measures altitude or elevation above sea level, which is not directly related to a vehicle's speed. Understanding these distinctions clarifies why the speedometer is specifically designed for tracking how fast you are moving on the road.