What is the actual speed when the car speedometer shows 100?

[CassidyRose]

When the dashboard displays a speed of 100 kilometers per hour, the actual speed may be approximately 97 kilometers per hour. The so-called positive error means that the measured value is never less than the actual value, that is, the speedometer reading can be equal to or greater than the actual value, but it must never be less than the actual value. Here is some additional information: Speedometer principle: The speedometer signal comes from a sensor. In some manual transmission vehicles, the speed sensor is located on the output shaft of the transmission, while in automatic transmission vehicles, the speed sensor comes from the wheel speed sensor of the ABS system. The sensor can measure the rotational frequency of the object being measured. For example, the wheel speed sensor can measure the rotational frequency of the wheel, and then the wheel speed can be calculated based on hardware parameters and time. Knowing the speed and combining it with the wheel diameter allows the vehicle speed to be calculated.