Which of the listed emergencies makes it impossible to use a passenger car in road traffic?

In accordance with Art. 66 of the Road Traffic Act, a vehicle must be maintained in a condition that does not endanger safety. Using a vehicle is impossible in the event of critical system failures, such as a faulty braking system or non-functioning 'stop' lights. Such a defect poses a direct threat on the road and, in the event of a police check, results in a fine and the confiscation of the registration certificate.