Land-use and transport planning – A field of complex cause-impact relationships. Thoughts on transport growth, greenhouse gas emissions and the built environment

The notion of integrated land-use and transport planning is linked to hopes that it may be possible to reverse the traffic-inducing effects of interactions between the built environment and transport, and to use planning interventions in land-use and transport provision to effectively contribute to the reduction of transport-related greenhouse gas emissions. However, the targeted design of mixed-use and compact structures on the local and regional level is superimposed by societal and spatial trends that make large-scale mobility politically desirable or necessary. Against this background, the aforementioned hopes appear clearly exaggerated. Written from a German, at times also a wider European perspective, this paper develops the following argument. Land-use and transport are indeed interrelated, but the historical transport growth we face is mainly driven by other societal factors, such as economic growth, the spatial division of labour, large-scale societal integration, and gender equity. In addition, the effects of land-use on transport are uncertain due to limited knowledge on cause-impact relationships. Even in cases where cause and impact can be established, the impact of planning is limited. We conclude that the scope of integrated land-use and transport planning on the local level should not be overestimated so as to avoid false hopes and corresponding failures. This type of planning can hardly be justified by arguments related to the prevention of carbon dioxide emissions, but is useful in pursuing other urban development goals, such as ensuring accessibility without the use of cars, providing a healthy and livable environment, and – to a lesser extent – shifting travel to other modes and, indeed, reducing it overall. Local and regional land-use and transport planning should be justified by realistic and achievable goals, while at the same time highlighting that it has little effect on the general increase in distances travelled and associated greenhouse gas emissions. Conversely, we conclude that the necessary reduction of emissions within the transport sector must be tackled by interventions on the national and supranational levels, rather than expecting or demanding success from largely ineffective, more local interventions and the actors involved with them.