Towards low carbon cities through land use and modal shifts: A case study of Yokohama.

摘要

Reducing transport sector emissions through changes in land use planning and modal shifts is one of the most important trends in environmental policy making in the present world. Numerous research projects have articulated the close relationship between gaseous emissions and land use planning, and many researchers have shown that land use and modal split variables can accurately predict gaseous emissions from the transport sector. Moreover, land use transportation models begun in 1960s are now thriving because of new needs for predicting the impact of global environmental challenges.This research aims to contribute to the mitigation of greenhouse gases (GHG) in urban areas by providing a model that can test the impacts of land use planning and modal shift policies. The research uses a modified version of a land use transportation model developed in Japan. The model uses microeconomic ideas and determines the trip and location changes for three main actors (households, service industry, and other industries).The city of Yokohama, Japan, is used for the modeling because of its positive attitude towards urban planning, extensive spatial and transportation data, and competitive edge in the Tokyo Metropolitan Area (TMA). The data used include the most recent version of a TMA person trip survey and the corresponding socio-economic and demographic data from the same period of time. The research tested two policies selected from the qualitative data: public transit promotion, as Yokohama owns its subways and has cooperated with private railway companies and car restraining policies, which were already introduced through the annual event, Car Free Day, a largely grass-roots initiative.The study illustrated that these policies can reduce GHGs by encouraging people to adopt more environmentally sustainable modes and relocating the actors to high dense neighborhoods. The model results showed 1.3% and 13.0% reduction respectively in emissions resulting from the policy changes.The results of this study can be useful for cities of the Non-Annex I countries in the Asia-Pacific region, which are not required to address GHG mitigation presently. The study promotes local-level policy making in the developing world to establish a framework for GHG mitigation.