Traffic Control Technologies
Traffic Control Technologies Traffic signals at highway intersections are a familiar traffic control technology. At signalized intersections, the trade-off between mobility and safety is brought into sharp focus. Procedures for developing traffic-signal control plans (allocating green time to conflicting traffic movements) have made significant advances over the years. Today, signals at critical intersections can be designed to respond quickly to prevailing traffic flows, groups of signals can be coordinated to provide a smooth through-flow of traffic, and, in some cases, computers control entire networks of signals. Still, at some level, the effectiveness of improvements in signal control is fundamentally limited by the reaction times and the driving behavior of the motoring public as well as the braking and acceleration performance of the vehicles they drive. This presents highway engineers with a formidable barrier.
In addition to traffic signal controls, numerous safety, navigational, and congestion-mitigation technologies are reaching the market under the broad heading of Intelligent Transportation Systems (ITS). Such technological efforts offer the potential to reduce traffic congestion and improve safety on highways by providing an unprecedented level of traffic control. There are, however, many obstacles associated with ITS implementation, including system reliability, human response, and the human/machine interface. Numerous traffic control technologies offer the potential for considerable improvement in the efficient use of the highway infrastructure, but there remain limits defined by vehicle performance characteristics and their human operators.
