Have You Ever Wondered? What is Transportation Demand Management?

From Wikipedia, the free encyclopedia

Transportation demand management or travel demand management (both TDM) is the application of strategies and policies to reduce automobile travel demand, or to redistribute this demand in space or in time.[1][2]

In transport as in any network, managing demand can be a cost-effective alternative to increasing capacity. A demand management approach to transport also has the potential to deliver better environmental outcomes, improved public health and stronger communities, and more prosperous and livable cities. The techniques of TDM, applied by government transport agencies, link with and supports community movements for sustainable transport.


Background :
The term TDM has its origins in the United States in the 1970s and 1980s, and is linked to the economic impacts of the sharp increase in oil prices during the 1973 oil crisis and the 1979 energy crisis. As long lines appeared at gas stations, it became self-evident that alternatives to single occupancy commuter travel needed to be provided in order to save energy, improve air quality, and reduce peak period congestion.[3]

The concepts of TDM borrowed from mainstream transport planning in Europe, which had never been based on assumptions that the private car was the best or only solution for urban mobility. For example the Dutch Transport Structure Scheme has since the 1970s required that demand for additional vehicle capacity only be met "if the contribution to societal welfare is positive", and since 1990 has included an explicit target to halve the rate of growth in vehicle traffic.[4]

Some cities outside Europe have also consistently taken a demand management approach to transport and land use planning, notably Curitiba, Brazil, Portland, Oregon and Vancouver, Canada.

Relatively low and stable oil prices during the 1980's and 1990's led to significant increases in vehicle travel, both directly because people chose to travel by car more often and for greater distances, and indirectly because cities developed tracts of suburban housing, distant from shops and from workplaces, now referred to as urban sprawl. Trends in freight logistics, including a movement from rail and coastal shipping to road freight and a requirement for just in time deliveries, meant that freight traffic grew faster than general vehicle traffic.

Because vehicle travel was increasing rapidly from 1980-2000, it follows that (with a few exceptions) the techniques of demand management were not widely or successfully applied during this period. Small-scale projects to provide alternatives to single occupant commuter travel were common, but generally were led from outside the mainstream of transport planning. However many of the techniques in the demand management toolbox were developed during this period.

The British Government's marked a change in direction. In the introduction to the White Paper, Prime Minister Tony Blair stated that

We recognise that we cannot simply build our way out of the problems we face. It would be environmentally irresponsible - and would not work.

A companion document to the White Paper called Smarter Choices researched the potential to "scale up" the small and scattered demand management initiatives then occurring across Britain, and concluded that the comprehensive application of these techniques could reduce peak period car travel in urban areas by over 20%.[6]

A [7] by the United States Federal Highway Administration, was also released in 2004 and also concluded that a more proactive approach to transportation demand was an important component of overall national transport strategy.

Why manage travel demand?
The need to manage travel demand has now become urgent for a number of converging reasons.

Oil prices have now passed the previous peak in 1980, and 95% of all energy used in transport is oil. Vehicle travel in the United States, which has been rising steadily since records began, began to level out before the fuel price increases and is now in decline.[8]. Part of this decline is likely to be people making fewer trips, with potentially far-reaching economic and social consequences. Countries and cities where the car is one of many travel choices are more likely to prosper, as people can choose to drive less but are still able to travel by transit, cycle safely, walk to local shops and facilities, or choose to work or study from home.

Transport systems are responsible for 23% of energy-related greenhouse gas emissions, and are increasing at a faster rate than any other energy using sector.[9] Demand management is central to the effort to reduce greenhouse gas emissions from urban transportation,[10]

Increases in vehicle travel are linked to a range of health problems including poor urban air quality, road injuries and fatalities, and reduced physical activity. The World Health Organisation released a [11] in 2003, and stated that:

We are concerned that current patterns of transport, which are dominated by motorised road transport, have substantial adverse impacts on health.

The efficacy of expanded roadways in managing traffic congestion is increasingly under challenge. Much of the traffic on new or expanded roads has been shown to be induced.

A growing sustainable transport movement is mobilising public demand for investment in safer, more livable cities with a greater range of travel choices.

There is a broad range of TDM measures, including:

Transportation Management Associations: leverage public and private funds to increase the use of ridesharing and other commuting options that reduce traffic congestion and improve air quality.
Including or improving pedestrian-oriented design elements, such as short pedestrian crossings, wide sidewalks and street trees.
Requiring users of parking to pay the costs directly, as opposed to sharing the costs indirectly with others through increased rents and tax subsidies.
Including and improving public transportation infrastructure, such as subway entrances, bus stops and routes.
Subsidizing transit costs for employees or residents.
Bicycle-friendly facilities and environments, including secure bike storage areas and showers. See Bicycle transportation engineering
Providing active transportation (AT) facilities including bike lanes and multi-use trails.
Flex-time work schedules with employers to reduce congestion at peak times
Congestion pricing tolls during peak hours.
Road space rationing by restricting travel based on license plate number, at certain times and places.
Workplace travel plans.
Roadspace reallocation, aiming to re-balance provision between private cars which often predominate due to high spatial allocations for roadside parking, and for sustainable modes.
Time, Distance and Place (TDP) Road Pricing, where road users are charged based and when, where and how much they drive. Some transportation experts believe TDP pricing is an integral part of the next generation in transportation demand management.