What does a speedometer measure?

A speedometer is an instrument located in a vehicle that specifically measures the speed at which the vehicle is traveling at any given moment. It does this by taking information from the vehicle's transmission or wheels and translating that data into a speed reading, which is typically displayed in miles per hour (MPH) or kilometers per hour (KPH).

Understanding the role of a speedometer is essential for safe driving, as it allows drivers to adhere to speed limits and maintain safe driving practices. Other options, such as measuring distance, temperature, or fuel efficiency, do not pertain to the main function of a speedometer. A vehicle typically uses an odometer to track distance traveled, a temperature gauge to monitor engine temperature, and fuel efficiency is often gauged through a different set of instruments or onboard diagnostics. Therefore, a speedometer's sole purpose revolves around providing an accurate representation of the vehicle's speed on the road.