When is vehicle 3 allowed to proceed?

The correct response indicates that vehicle 3 is allowed to proceed after vehicles 1 and 2 have moved, which typically follows traffic control rules and the principle of right-of-way. In many traffic situations, particularly at intersections or in scenarios involving multiple vehicles, the order in which vehicles can proceed is important for safety and efficiency.

By prioritizing vehicles 1 and 2, the system ensures that those with the right-of-way are allowed to go first, reducing the potential for collisions and confusion. This approach is consistent with standard traffic laws which state that vehicles must yield to others that have established right-of-way.

Additionally, the other options present potential misunderstandings regarding the rules of the road. For example, proceeding whenever a green light is seen does not account for other vehicles that may have priority. Moving before vehicles 1 and 2 contradicts the principle of following the right-of-way rules, and the stipulation of only proceeding at night is irrelevant to the traffic dynamics described. These options could lead to unsafe driving behaviors by allowing vehicles to act without regard to established traffic protocols. Therefore, the choice of vehicle 3 proceeding after vehicles 1 and 2 aligns with common traffic practices and contributes to overall road safety.