TRAFFIC FLOW CONTROL. IN: HANDBOOK OF TRANSPORT SYSTEMS AND TRAFFIC CONTROL

The most common objective of traffic control is to expedite traffic or increase the capacity of a transportation facility. However, occasionally it is intended to slow down traffic. Traffic control can be very simple or it can be very complex, requiring the implementation of a range of traffic control devices, surveillance, communication, and forecasting. Traffic engineers typically monitor a range of road operating conditions in order to understand traffic conditions both before and after a strategy is implemented. Traffic control also often requires an estimate of traffic parameters in order to predict the performance of a traffic control strategy. Traffic control strategies can vary greatly in terms of the degree of control they provide, implementation costs, applications, technological requirements and institutional considerations. Traffic control strategies such as road markings and traffic signs, intersection signalization and coordination, ramp metering, traffic advisory and information systems, limited access lanes, road pricing, incident and emergency management systems, advanced vehicle control and safety systems, and traffic calming are briefly summarized.