Reza Mohammadi

The management and control of traffic congestion requires both provision of adequate highway capacity, through expansion and extension of road infrastructure, and demand management strategy to control the level of demand in certain corridors, maximise the use of available capacity, encourage use of alternative travel modes and provide advance travel information to trip makers. The extension and expansion of road nfrastructure is not always possible particularly in dense urban areas, where land is scarce, and not necessarily the best solution as it is a relatively lengthy process and costly. Experience from many cities across the World has shown that any additional capacity provided through new road schemes is usually taken up by suppressed demand and induced trips. There therefore needs to be a balance between supply and demand optimising the use of transport supply and managing the demand. The overall transport strategy has to be based on an integrated transport plan detailing the different elements of the plan including infrastructure development, both road and transit, supporting policies and demand management measures as well as a timeline for phasing and implementation plan. The many demand management measures developed over the years provide a useful Toolkit for transport planners and engineers to select the most appropriate measures suitable for local conditions for reducing and redistributing the travel demand in order to maintain and control traffic congestion. Some of these measures are aimed at reducing car travel, such as parking control and road user charges, some are aimed at shifting mode of travel and encouraging the use of public transport, such as bus priority, bus lanes and cycle lanes, and others are aimed at maximising the use of available road capacity through signal optimisation and coordination, high occupancy vehicle lanes and provision of advance travel information. This paper presents the various elements of demand management Toolkit and discusses their effectiveness in controlling and managing traffic congestion. It also provides examples where these measures have been applied and how effective they have been in controlling traffic congestion.