Final answer:
The answer is a policeman. You must obey a policeman's directions over other traffic signals as they have the authority to override automated traffic controls and respond to real-time situations.
Step-by-step explanation:
When faced with the choice of obeying a steady red light, a stop sign, a flashing red light, or a policeman, you must always obey the policeman over the other signals. This is because a police officer on the road can assess the situation in real-time and might be directing traffic in response to an emergency or a road condition not visible to a driver. For instance, even if you encounter a red traffic signal, if a policeman is present and is directing traffic differently, perhaps due to an emergency or an incident ahead, you must follow the officer's commands.
Furthermore, traffic signals are designed to regulate traffic flow and improve safety, particularly at intersections where vehicles may otherwise speed through without regard. However, the real-time directives of a law enforcement officer can override these automated signals if deemed necessary for safety or other considerations. A citizen's understanding of a police officer as a source of legitimate authority is critical in this respect, as police have the right to pull over vehicles, issue tickets, or direct traffic, which is part of their official duties.