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Travel demand management (TDM) in Asia

Motorization in Asia's rich and poor cities is increasing rapidly. As incomes rise continued motorization can be expected, but the growth path actually taken can be influenced by adoption of appropriate transport and TDM policies.

Policies are needed that reduce demand for private car travel (measured in vehicle-km) and promote increases in public transport use. The most effective TDM policies are those that are successfully able to address the time and locational aspects of congestion.

There are severe constraints in financial resources in many cities and many problems to be addressed. Hence, there is an urgent need for low cost improvement measures.

In many cities in Asia today there is a bias in favor of private modes rather than public transport. The result is that public transport's share of the transport task is usually declining. Public transport should desirably be the dominant mode but this cannot be achieved without the implementation of sound and comprehensive TDM policies. However, a modest road network is required to support the arrangement of land uses, public transport operations and other essential vehicle travel. This means that in some cases additional road infrastructure will have to be created to enable successful TDM schemes to be implemented.

By its nature TDM involves a multitude of agencies within and outside the transport sector. It consists of many measures covering physical and "soft" measures (policies, pricing). It is therefore complex and a multi-agency activity that frequently causes problems in implementation.

TDM measures (all types) should not be implemented in isolation but in conjunction with other transport planning and TSM measures. TDM is essential to support other initiatives (e.g. promotion of public transport).

All TDM measures even when directed to air quality improvement should be safe and designed taking into account the needs of users in order to make them acceptable and implementable. Parking policy is a valuable TDM measure, however, many cities in Asia do not have a well thought out policy on parking. Parking provision (quantity, location and price) affects the demand for travel (for non-through trips only). Because parking and roads are jointly demanded there is a case to price parking at much higher than the cost of provision.

Parking policy should be metropolitan in scope so that city center parking controls do not encourage urban sprawl.

Restraints on traffic may take a number of forms including physical measures that impact on vehicle use to policies that are designed to reduce vehicle ownership. Cities throughout the region have implemented various physical schemes including: truck bans, traffic-calmed areas, and pedestrian schemes that exclude traffic. Bans exclude certain vehicle types and the costs imposed may sometimes be considerable. Small area-based limitation schemes rarely affect the decision to travel or the mode of travel but may change the distribution of travel. The impacts and appropriateness of each type of scheme therefore needs to be individually considered.

Wide-scale odd-even number plate schemes may affect the mode of travel in the short term but may have unforeseen perverse effects. While these schemes may bring temporary relief they are unlikely to provide the basis for an appropriate long-term solution. If there is temporary relief from congestion, then the opportunity should be used appropriately to implement schemes with long term beneficial effects (e.g. implementation of bus lanes in a street in which traffic volumes have declined).

Policies aimed at reducing vehicle ownership such as rationing schemes and/or high taxes and charges that have been adopted in Singapore, Hong Kong and Shanghai are rarely effective on their own. They would usually need to be supplemented directly by physical or pricing measures that influence vehicle use.

Go to the BAQ 2004 website
Vehicular air pollution > Transportation and traffic management

Secretariat: The World Bank & Asian Development Bank