By centrally controlling the ramp meters within a network, traffic bottlenecks or accidents/incidents that occur several miles ahead can be detected, optimizing further the benefits of ramp metering. Furthermore, metering rates can be balanced among the ramps within the network, promoting equity. Many cities prefer centrally controlled ramp metering as it allows for more extensive monitoring, easier system override, and it improves performance of the transportation system. However, central controllers are very expensive and are more beneficial where recurring congestion exists.
Traffic responsive controllers normally react to, rather than prevent congestion.