Wider roads, more cars

Abstract

The transport policy currently followed in many European cities seems to be a combination of investments in public transport in order to increase, or at least maintain, its market share, and road building in order to keep up with expected traffic growth. Apparently, there is a prevalent belief among policy makers that increased road capacity in urban areas does not in itself cause any growth in car traffic worth mentioning. Such a belief neglects the simple economic theory of supply and demand, as well as more specific theories about the dynamics of traffic under congested conditions. An empirical study of commuting patterns in two transport corridors in Oslo, Norway, shows that a considerable proportion of commuters are sensitive to changes in the speed of the respective modes of transportation. The mode chosen depends to a large extent on the ratio of door‐to‐door travel times by car and transit. Freer flowing traffic in the road network will induce a higher proportion of commuters to travel by car. Conversely, faster public transport will reduce the proportion of car commuters, but the effects of such improvements will be offset if road capacity is simultaneously increased. In addition to the relative speeds of car and transit, the parking conditions at the workplace are of great importance to the choice of transport mode.

Do Road Planners Produce More ‘Honest Numbers’ than Rail Planners? An Analysis of Accuracy in Road‐traffic Forecasts in Cities versus Peripheral Regions

“…exogenously given total future amounts of traffic, where the traffic in the analysed alternatives differ only in their distribution between different parts of the road network) were used in spite of the fact that the same analyses showed a breakdown of traffic flows on large proportions of the road network in a decade or two if the road capacity was not increased. However, if congestion really grew that bad, many peak-period motorists would choose to go by public transport, bicycle or foot instead of driving (Mogridge, 1997;Naess et al, 2001;Cairns et al, 2002;Noland and Lem, 2002).…”

Indirect Effects to Include in Strategic Environmental Assessments of Transport Infrastructure Investments

“…According to the Downs-Thomson paradox (Downs, 1962;Thomson, 1977) in the long run this can make things worse for both automobile and public transport. According to Mogridge (1990), increased road capacity in congested areas will in the long run only increase flow, not speed, and thus be counter-productive (see also the discussion by Naess et al, 2001). When new roads initially mean less congestion, the automobile will certainly gain popularity and some former passengers of public transit will switch to the private alternative.…”

“…Today it is an acknowledged fact among most of the researchers in the field that new or improved connections in the transport system generate new traffic (e.g. SACTRA, 1994;Goodwin, 1996;Naess et al, 2001;Noland and Lem, 2002). There is, however, no thorough view of how large these effects are in each individual case.…”

“…Improved road infrastructure, for example, could steal competitive power from rail-bound collective traffic due to changes in the travel time ratio between to two mentioned modes of travel (e.g., see the Oslo case in Naess et al, 2001).…”

Knowledge-based land use and transport planning? Consistency and gap between “state-of-the-art” knowledge and knowledge claims in planning documents in three Scandinavian city regions

“…Among suburbanites, there is still a tendency of higher use of public transport among those who live in areas with a high level of public transport accessibility (Naess, Røe & Larsen, ibid. ;Naess, Mogridge & Sandberg, 2001;Hartoft-Nielsen, 2001a). Some influence of proximity to local centers or local service facilities on travel behavior has also been found in some studies, but in the Nordic countries this influence has generally been found to be considerably weaker than that of distance to the main city center (e.g.…”