Final answer:
The signal used at congested stations for managing the flow of traffic and ensuring safety is called a traffic signal. It serves to regulate vehicle speeds and facilitate pedestrian crossing, reducing accidents.
Step-by-step explanation:
The type of signal used at congested stations to close-in trains is known as a traffic signal. A traffic signal is essential for managing the flow of traffic with high densities, particularly at busy intersections near campuses where pedestrians, including students, need to cross safely.
The implementation of a traffic signal contributes to pedestrian safety, encourages vehicles to slow down and comply with the posted speed limits, and overall reduces the likelihood of accidents, some of which may have fatal consequences.