Why is a decrease of pressure of more than 0.7 bar problematic in the compressed air system of a motor vehicle, if you press the brake pedal fully down one time (cut-off pressure around 10 to 13 bar)?

The selected combination of answers is correct because both points address critical aspects of the braking system's functionality.

Firstly, a rapid decrease in air supply (more than 0.7 bar) means that, if the driver needs to brake again shortly after the initial braking, there may not be sufficient air pressure left to provide adequate braking power. This could lead to a dangerous situation, especially in emergency braking scenarios.

Secondly, when the braking action deteriorates, it directly impacts the vehicle's ability to stop effectively, which can have serious safety implications. According to German traffic regulations, vehicles must have functioning brakes capable of performing reliably under various conditions.

Understanding these aspects is crucial for both maintaining vehicle safety and complying with legal requirements outlined in the Straßenverkehrsordnung (StVO), the German Road Traffic Regulations.