Mobility Management


Impact of the Transport System on the Local Spatial Structure and on Mobility Patterns

The "Law of Conservation of Travel Time"

The empirical mobility research of the last thirty years indicates a connection between reduction of travel time by development of the transport system and changes in the travel and spatial behaviour of firms and households, which lead to overall constant travel time budgets accompanied by increasing trip distances. The visible structural effects of local bypasses or highway junctions near settlements, in particular the sprawl effects (detached family houses, shopping centres) emphasise this hypothesis of constant travel time budgets on the long run. This so called induced traffic is subject of recent discussions in transport research disciplines. In some ex ante-assessments of infrastructure projects the induced traffic is integrated in the traffic forecast. An additional step deals with the assumption that new infrastructure projects generate a more dynamic spatial development in the regions directly connected to the infrastructure project. But no rules or robust numerical assessment tools are available dealing with these effects at the moment.
Further Readings & Links

Mobility in Germany 2002 - continuing data collection on mobility behaviour in Germany.

Postal Cars in Switzerland provice access to villages that are not connected to the railway system (Source: CIPRA) .
TRANSLAND provides a comprehensive overview of the current state of the art and state of the practice in transport and land use planning in urban areas in the EU. They found the following conclusions concerning sustainability:

  • Land-use and transport policies are only successful with respect to criteria essential for sustainable transport (reduction of travel distances and travel time and reduction of share of car travel) if they make car travel less attractive (i.e. more expensive or slower).
  • Land-use policies to increase urban density or mixed land-use without accompanying measures to make car travel more expensive or slower have only little effect as people will continue to make long trips to maximise opportunities within their travel cost and travel time budgets. However, these policies are important in the long run as they provide the preconditions for a less car-dependent urban way of life in the future. But transport policies making car travel less attractive (more expensive or slower) are very effective in achieving the goals of reduction of travel distance and share of car travel.
  • However, they depend on a spatial organisation that is not too dispersed.
  • Highly diversified labour markets and different work places of workers in multiple worker households set limits to a optimum co-ordination of work places and residences.
  • Furthermore, large spatially not integrated retail and leisure facilities increase the distance travelled by car and the share of car travel.
  • Therefore, land-use policies to prevent the development of such facilities ("push") are more effective than land-use policies aimed at promoting high density, mixed-use development ("‘pull").
  • Fears that land-use and transport policies designed to constrain the use of cars in city centres are detrimental to the economic viability of city centres have in no case been confirmed by reality (except in cases where at the same time massive retail developments at peripheral green field locations have been approved).
  • Transport policies to improve the attractiveness of public transport have in general not led to a major reduction of car travel, attracted only little development at public transport stations, but contributed to further suburbanisation of population.
In summary, if land-use and transport policies are compared, transport policies are by far more direct and efficient in achieving sustainable urban transport. However, accompanying and in the long run supporting land-use policies are essential for creating less car-dependent cities (PAULLEY & PEDLER 2000).

These general conclusions for urban areas are transferable to urban areas in the Alpine region as well. In peripheral regions a stronger connection between settlement development and the transport system is needed:
  • Shopping centre regulations for guiding the locations of retail over 400 m2
  • Connection between financial aid for housing and the existence of public transport nearby.
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UNCEM (2007)
This article describes the results of the "Future in the Alps" project about leisure, tourism and commuter mobility.