Final answer:
Slower vehicles should use the rightmost lane when moving slower than the traffic flow to allow faster vehicles to pass. Traffic signals control speeds for safety and enhance pedestrian safety at intersections.
Step-by-step explanation:
Vehicles moving slower than the traffic flow should typically use the rightmost lane, or the lane furthest from oncoming traffic in countries where driving is on the right side of the road. This enables faster-moving vehicles to pass safely on the left. Traffic signals are established to control traffic flow, making all vehicles, regardless of speed, slow down for safety and regulate their speeds according to the posted speed limit. Slow-moving vehicles, such as a gray-haired old man guilty of "DWE," driving while elderly, should not obstruct the flow of traffic more than necessary. Additionally, traffic signals enhance pedestrian safety around busy intersections, especially where students and others need to cross the street safely without dodging passing cars.