When does the speed limiter have to be tested?

The speed limiter's testing requirements are important for ensuring vehicle compliance with regulations that promote road safety. According to German traffic laws, specifically the Road Traffic Licensing Regulations (StVZO), certain changes to a vehicle require the speed limiter to be tested.

1. After any change of the effective circumference tyre size: Changing tyre sizes can affect the vehicle's speed and performance, potentially leading to unsafe conditions if the speed limiter settings are not adjusted accordingly.

2. After any change of the fuel supply device: Modifying the fuel system can impact the engine's power output and efficiency, again necessitating a check to ensure that the speed limiter is functioning correctly to maintain safety.

The regulation ensures that the vehicle remains within safe operating limits, as an improperly calibrated speed limiter could lead to excessive speeds and increase the risk of accidents. It's crucial to choose all relevant options in such questions to fully understand the implications of vehicle modifications on safety and compliance.