If the traffic signal is red, what should vehicles do?

Answer: B — Vehicles should not pass the light and wait behind the stop line

When the traffic signal is red, vehicles must come to a complete stop and remain behind the stop line. This action is crucial for maintaining road safety and ensuring that traffic flows in an organized manner. Stopping at a red light allows pedestrians to cross safely and helps prevent accidents at intersections where vehicles could collide if they disregarded the signal. Waiting behind the stop line signifies that a driver respects traffic regulations and is aware of their responsibility to control their vehicle in response to signals. This is particularly important in urban areas where pedestrian traffic may be high and where failure to stop could lead to severe consequences.