What do Ramp Meters help to manage on highways?

Ramp meters are specially designed traffic control devices that are placed at highway on-ramps to regulate the flow of vehicles entering the highway. By controlling the number of vehicles that can enter the highway at any given time, ramp meters help to prevent congestion and maintain a smooth flow of traffic on the main thoroughfare. This management is essential because it reduces the chances of bottlenecks that can occur when too many vehicles try to enter the highway simultaneously.

The primary function of ramp meters is to create gaps in the traffic flow, allowing vehicles already on the highway to maintain a safer and more consistent speed. This not only enhances safety but also improves the overall efficiency of highway operations. In contrast, the other options relate to different aspects of traffic management: speed limits pertain to controlling vehicle speed rather than entry, traffic signals regulate intersection flows, and managing the length of traffic jams involves broader traffic management strategies rather than the specific task that ramp meters are designed for.