Final answer:
Drivers are not allowed to enter intersections during heavy traffic unless they can cross without stopping, to prevent traffic jams and accidents.
Step-by-step explanation:
During heavy traffic, drivers are prohibited from entering any intersection unless they are certain they can clear it without stopping. This rule is in place to ensure traffic flow and prevent gridlock that can occur when vehicles are stuck in the middle of an intersection due to heavy traffic on the other side. The installation of traffic signals helps control this by regulating the flow of cars, thereby reducing the likelihood of congestion and accidents. It also significantly improves pedestrian safety, as people can cross at designated times without having to dodge traffic. In areas where traffic volume has increased dramatically due to new developments, like manufacturing plants or increased business activity, traffic signals have become an essential measure. Moreover, these signals are critical in places with a high incidence of accidents to reduce the number of collisions and potential fatalities.