In the following cases, you must not enter a crossroad, even though the traffic light shows "green": with slow-moving traffic, as crossings, for example, must remain free for emergency vehicles. Secondly, when police officers regulate traffic and give instructions that deviate from the meanings of the colors of the traffic lights. In general, a green traffic light tells you that you are allowed to drive and overrules other traffic signs that regulate the right of way. Policeman orders have the highest rank and override traffic lights.