Final answer:
When encountering a red arrow signal, one must stop and yield before turning, following local traffic laws. A traffic signal's installation at an intersection is based on the need for safety and orderly traffic control, particularly in areas with high pedestrian traffic and vehicle speeds that could lead to increased accidents.
Step-by-step explanation:
When you encounter a red arrow signal at an intersection, the rules of the road generally require you to come to a complete stop and yield to oncoming traffic and pedestrians before proceeding. However, the question posed suggests that you may be able to turn after stopping even against a red signal. Traffic rules can vary by jurisdiction, so it's important to follow local traffic laws and signs. The need for a traffic signal at a particular intersection is often determined by factors such as vehicle speed, pedestrian safety, and accident rates.
A traffic signal serves to regulate vehicle and pedestrian movements for increased safety and efficiency. It's not uncommon for high-traffic intersections near campuses or other areas to necessitate a traffic signal to protect pedestrians who must otherwise navigate busy roads. For instance, at an intersection where vehicles typically speed and disregard the speed limit, a traffic signal can effectively calm traffic flow and prompt vehicles to slow down. Furthermore, it provides clear prompts for when pedestrians have the right of way, enhancing their safety and mitigating the risk of accidents.
The decision to install a traffic signal at an intersection usually follows an investigation into several concerns, including but not limited to excessive speeding, the frequency of near-misses or actual collisions, and incidents that have resulted in injuries or fatalities. The installation of a signal is usually motivated by the overarching goal of reducing accidents, which have been shown to occur frequently or have resulted in significant consequences at that location. The decision-makers would weigh these reasons with substantial evidence like police reports or traffic studies to justify the addition of a traffic signal.