Transportation demand management or travel demand management (TDM) is the application of strategies and policies to increase the efficiency of transportation systems, that reduce 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, stronger communities, and more prosperous cities. [3] TDM techniques link with and support community movements for sustainable transport.
The Association for Commuter Transportation defines TDM as the use of strategies to inform and encourage travelers to maximize the efficiency of a transportation system leading to improved mobility, reduced congestion, and lower vehicle emissions. [4]
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. When 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. [5]
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 be met only "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. [6]
Some cities outside Europe have also consistently taken a demand management approach to transport and land use planning, notably Curitiba, Brazil; Portland, Oregon, US; Arlington, Virginia, US; [7] and Vancouver, Canada.
Relatively low and stable oil prices during the 1980s and 1990s 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 to 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 White Paper on Transport [8] 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 sustainable transport 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%. [9]
A similar study [10] by the United States Federal Highway Administration, [11] 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.
In 2023, the Biden-Harris Administration released the U.S. National Blueprint for Transportation Decarbonization. Developed by the Departments of Energy, Transportation, Housing and Urban Development, and the Environmental Protection Agency, the Blueprint is a landmark strategy for cutting all greenhouse emissions from the transportation sector by 2050.
The Blueprint recommends the use of Transportation Demand Management (TDM) strategies, policies, and regulations to increase the efficiency of our transportation systems. The Blueprint states, "it is essential to implement design solutions that increase convenience, provide better access to clean modes of travel, and support demand management policies that make it easier and more convenient to choose more efficient travel options".
Since 2010 transportation professionals have suggested that the TDM is widely misunderstood simply as a collection of vaguely related initiatives, and that this misunderstanding is constraining the true potential of the concept. TDM practitioners have found that TDM is far more effective when framed as a philosophical approach which over time becomes a cornerstone of sustainable urban transport systems. A new paradigm in transport planning, internationally recognised as TDM, appears to be emerging which embraces concepts such as "mobility management" and "active travel management" under its umbrella. [12]
Crucial to the delivery of a sustainable urban transport system is integrating the TDM philosophy into urban transport planning, as well as the daily management and operation of transport services and infrastructure. It appears that managing travel demand has largely been compartmentalized as a set of “soft measures” to promote sustainable travel options or programs to promote and offer shared ride arrangements. Demand management means different things to different disciplines. For example: to Information Technology (IT) specialists, managing demand is new technology to provide information; to operations managers, managing demand is controlling the flow onto highways; to economists, it is pricing the system to find equilibrium with capacity; to marketers, it is promoting innovative campaigns; and to many policymakers TDM remains a largely unknown entity.
The concept has become confused as each discipline has tried to mold the concept to their set of tools. This “silo” thinking inhibits the kind of policy integration that is needed to develop a sustainable urban transport solution strategy. There remains much confusion as to what a sustainable transport system would comprise. It is helpful therefore to consider different approaches to sustainable transport along a spectrum of viewpoints, ranging from weak to strong sustainability. [13] Generally efforts to address the impact of transport on climate change to date have been largely focused on technology. The impact of this technological-led approach has been very limited in the transport sector. TDM has the potential to move the transport sector from a position of weak to strong sustainability by combining behavior-change with technology improvements.
In this context transport demand management is understood as a much broader concept. Implicit in the use of the term is the assumption that it is accompanied by the implementation of sustainable mobility, introduction of full cost pricing and organizational or structural measures to ensure a broad range of complementary interventions work effectively together to realize the benefits of sustainable transport. It is the unifying philosophy of TDM, not specific measures associated with it, that underpin the policy objective of a more sustainable system of transport. This philosophy of managing demand accepts that meeting unfettered demand for travel is impractical and that therefore the system needs to be managed. That demand for travel needs to be managed by:
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, started to level out before the fuel price increases and is now in decline. [14] 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. [15] Demand management is central to the effort to reduce greenhouse gas emissions from urban transportation, [16]
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 Organization stated in 2003: [17]
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.
Air travel demand mitigation or aviation demand reduction [19] [20] [21] or air travel demand reduction [22] [23] [24] [25] is a part of transportation demand management and climate change mitigation. [26] [27]
Inhibition of a large or general growth in demand or reduction of demand and need for flights is considered an important part of climate change mitigation as air travel has a substantial impact on the climate. Changes in "behavioral travel parameters can significantly impact the projections for travel demand and the associated energy use and CO2 emissions". [28]This section needs additional citations for verification .(January 2008) |
There is a broad range of TDM measures, including:
Transport economics is a branch of economics founded in 1959 by American economist John R. Meyer that deals with the allocation of resources within the transport sector. It has strong links to civil engineering. Transport economics differs from some other branches of economics in that the assumption of a spaceless, instantaneous economy does not hold. People and goods flow over networks at certain speeds. Demands peak. Advance ticket purchase is often induced by lower fares. The networks themselves may or may not be competitive. A single trip may require the bundling of services provided by several firms, agencies and modes.
Road pricing are direct charges levied for the use of roads, including road tolls, distance or time-based fees, congestion charges and charges designed to discourage the use of certain classes of vehicle, fuel sources or more polluting vehicles. These charges may be used primarily for revenue generation, usually for road infrastructure financing, or as a transportation demand management tool to reduce peak hour travel and the associated traffic congestion or other social and environmental negative externalities associated with road travel such as air pollution, greenhouse gas emissions, visual intrusion, noise pollution and road traffic collisions.
Congestion pricing or congestion charges is a system of surcharging users of public goods that are subject to congestion through excess demand, such as through higher peak charges for use of bus services, electricity, metros, railways, telephones, and road pricing to reduce traffic congestion; airlines and shipping companies may be charged higher fees for slots at airports and through canals at busy times. Advocates claim this pricing strategy regulates demand, making it possible to manage congestion without increasing supply.
In economics, induced demand – related to latent demand and generated demand – is the phenomenon whereby an increase in supply results in a decline in price and an increase in consumption. In other words, as a good or service becomes more readily available and mass produced, its price goes down and consumers are more likely to buy it, meaning that quantity demanded subsequently increases. This is consistent with the economic theory of supply and demand.
Sustainable transport refers to ways of transportation that are sustainable in terms of their social and environmental impacts. Components for evaluating sustainability include the particular vehicles used for road, water or air transport; the source of energy; and the infrastructure used to accommodate the transport. Transport operations and logistics as well as transit-oriented development are also involved in evaluation. Transportation sustainability is largely being measured by transportation system effectiveness and efficiency as well as the environmental and climate impacts of the system. Transport systems have significant impacts on the environment, accounting for between 20% and 25% of world energy consumption and carbon dioxide emissions. The majority of the emissions, almost 97%, came from direct burning of fossil fuels. In 2019, about 95% of the fuel came from fossil sources. The main source of greenhouse gas emissions in the European Union is transportation. In 2019 it contributes to about 31% of global emissions and 24% of emissions in the EU. In addition, up to the COVID-19 pandemic, emissions have only increased in this one sector. Greenhouse gas emissions from transport are increasing at a faster rate than any other energy using sector. Road transport is also a major contributor to local air pollution and smog.
A living street is a street designed with the interests of pedestrians and cyclists in mind by providing enriching and experiential spaces. Living streets also act as social spaces, allowing children to play and encouraging social interactions on a human scale, safely and legally. Living streets consider all pedestrians granting equal access to elders and those who are disabled. These roads are still available for use by motor vehicles; however, their design aims to reduce both the speed and dominance of motorized transport. The reduction of motor vehicle dominance creates more opportunities for public transportation. Living Streets achieve these strategies by implementing the shared space approach. Reducing demarcations between vehicle traffic and pedestrians create a cohesive space without segregating different modes of transportation. Vehicle parking may also be restricted to designated bays. These street design principles first became popularized in the Netherlands during the 1970s, and the Dutch word woonerf is often used as a synonym for living street.
Land transport is the transport or movement of people, animals or goods from one location to another location on land. The two main forms of land transport can be considered to be rail transport and road transport.
The European Local Transport Information Service (ELTIS) is a non-profit European portal for local transport news and events, transport measures, policies and practices implemented in cities and regions in Europe.
Road space rationing, also known as alternate-day travel, driving restriction and no-drive days, is a travel demand management strategy aimed to reduce the negative externalities generated by urban air pollution or peak urban travel demand in excess of available supply or road capacity, through artificially restricting demand by rationing the scarce common good road capacity, especially during the peak periods or during peak pollution events. This objective is achieved by restricting traffic access into an urban cordon area, city center (CBD), or district based upon the last digits of the license number on pre-established days and during certain periods, usually, the peak hours.
Transport or transportation is the intentional movement of humans, animals, and goods from one location to another. Modes of transport include air, land, water, cable, pipelines, and space. The field can be divided into infrastructure, vehicles, and operations. Transport enables human trade, which is essential for the development of civilizations.
Active mobility, soft mobility, active travel, active transport or active transportation is the transport of people or goods, through non-motorized means, based around human physical activity. The best-known forms of active mobility are walking and cycling, though other modes include running, rowing, skateboarding, kick scooters and roller skates. Due to its prevalence, cycling is sometimes considered separately from the other forms of active mobility.
Aimsun Live is a traffic forecasting solution based on simulation, developed and marketed by Aimsun.
Shared transport or shared mobility is a transportation system where travelers share a vehicle either simultaneously as a group or over time as personal rental, and in the process share the cost of the journey, thus creating a hybrid between private vehicle use and mass or public transport. It is a transportation strategy that allows users to access transportation services on an as-needed basis. Shared mobility is an umbrella term that encompasses a variety of transportation modes including carsharing, Bicycle-sharing systems, ridesharing companies, carpools, and microtransit.
The environmental effects of transport are significant because transport is a major user of energy, and burns most of the world's petroleum. This creates air pollution, including nitrous oxides and particulates, and is a significant contributor to global warming through emission of carbon dioxide. Within the transport sector, road transport is the largest contributor to global warming.
Public transport is a system of transport for passengers by group travel systems available for use by the general public unlike private transport, typically managed on a schedule, operated on established routes, and that charge a posted fee for each trip. There is no rigid definition of which kinds of transport are included, and air travel is often not thought of when discussing public transport—dictionaries use wording like "buses, trains, etc." Examples of public transport include city buses, trolleybuses, trams and passenger trains, rapid transit and ferries. Public transport between cities is dominated by airlines, coaches, and intercity rail. High-speed rail networks are being developed in many parts of the world.
Urban freight distribution is the system and process by which goods are collected, transported, and distributed within urban environments. The urban freight system can include seaports, airports, manufacturing facilities, and warehouse/distribution centers that are connected by a network of railroads, rail yards, pipelines, highways, and roadways that enable goods to get to their destinations.
The Sustainable Transport Award (STA), is presented annually to a city that has shown leadership and vision in the field of sustainable transportation and urban livability in the preceding year. Nominations are accepted from anyone, and winners and honorable mentions are chosen by the Sustainable Transport Award Steering Committee.
Cars affect many people not just drivers and car passengers. The externalities of automobiles, similarly to other economic externalities, are the measurable difference in costs for other parties to those of the car proprietor, such costs not taken into account when the proprietor opts to drive their car. According to Harvard University, the main externalities of driving are local and global pollution, oil dependence, traffic congestion and traffic collisions; while according to a meta-study conducted by the Delft University these externalities are congestion and scarcity costs, accident costs, air pollution costs, noise costs, climate change costs, costs for nature and landscape, costs for water pollution, costs for soil pollution and costs of energy dependency.
Mobility as a service (MaaS) is a type of service that, through a joint digital channel, enables users to plan, book, and pay for multiple types of mobility services. The concept describes a shift away from personally-owned modes of transportation and towards mobility provided as a service. This is enabled by combining transportation services from public and private transportation providers through a unified gateway that creates and manages the trip, which users can pay for with a single account. Users can pay per trip or a monthly fee for a limited distance. The key concept behind MaaS is to offer travelers mobility solutions based on their travel needs.
Air travel demand mitigation or aviation demand reduction or air travel demand reduction is a part of transportation demand management and climate change mitigation.