Final answer:
The left signal on a regular traffic light controls the flow of vehicles, ensuring they slow down to the speed limit and allowing pedestrians to cross safely. It's installed with two wires, balancing tensions to support its weight.
Step-by-step explanation:
The left signal on a regular traffic light works to ensure both vehicle safety and pedestrian safety. Multiple vehicles speeding through an intersection can be hazardous; thus, a traffic light regulates their flow by making vehicles slow down and stop when necessary. This is particularly important as it prevents them from speeding through the signal, which is often set at the posted speed limit.
Furthermore, at busy intersections near campuses where students and others frequently cross, a left signal on a traffic light provides a designated time for pedestrians to cross safely. Without this signal, pedestrians would have to dodge traffic, which can be dangerous.
In terms of physical installation, a traffic light is typically suspended from two wires with attention paid to the forces involved. A free-body diagram would show all the forces acting on the traffic light, with the horizontal components of tension from the wires canceling each other out, and the vertical components adding up to equal the weight of the light.