Is the speedometer in your car accurate?

The average car speedometer may be off by a few mph

There are several GPS and 3rd party apps that show your actual speed

The speedometer, of course, tells you how fast or slow your car is moving when you’re behind the wheel.

The traditional speedometer shows a hand that raises or lowers, or swings left and right, when you accelerate or decelerate. Digital speedometers show you digits to display mph (or kilometers). But are these numbers accurate?

There are many ways to calculate the speed of a car while driving, whether it's the traditional speedometer, a GPS app, a third-party speedometer app or worst-case scenario, a police speed trap. No matter which method you use to track your speed, make sure you are respecting the posted speed limit.

How do speedometers work?

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