Can land use planning help mitigate transport-related carbon emissions? A case of Changzhou

Planners, engineers, and policymakers take a great interest in effective ways to mitigate carbon emissions by land use planning. Hence, the interrelationship between land use and carbon emissions has become a mutually concerned issue with the rapid economic growth and urbanization in the world. As the second largest source of carbon emissions, it has been argued whether transport-related emissions could be reduced by spatial planning and land use policy, since land use pattern, which affects urban form and configuration, is the origin of travel behaviors and has a close interaction with transport system. In this study, a traffic assignment model is incorporated with carbon emission evaluation at an individual trip level based on Origin-Destination person trip data in Changzhou, China, taking into account road types, capacity, velocity, and volume. On the other hand, land use pattern and landscape metrics are analyzed based on Traffic Analysis Zones (TAZ) which are the basic geographic unit for person trip survey and transport planning. Then, by using the traffic assignment results we investigate the spatial distribution pattern of carbon emitted by person trips at the level of road link, and examine whether transport-related carbon emissions are correlated to land use pattern. Our study observes that the distribution of land use pattern and transport-related carbon emissions varies considerably between urban and rural areas, and arterial and collector streets inside built-up area are the major contributors of carbon emissions rather than major road, highway, or expressway. A regression analysis demonstrates that land use and landscape pattern are significantly correlated with transport-related carbon emissions. The correlations between carbon emission intensities, land for residential and commercial uses, and patch density (PD) shape inverted-U curves, which are consistent with the trends shown in the Kuznets Curve. Findings of this study are further developed to provide policy implications to resolve China's low-carbon urban development. Since the Kuznets Curves do exist for the observed correlations between carbon emissions and land use, corresponding land use strategies like mixed high-density land use, compact city, etc. deserve more attention.