Life cycle assessment of a road investment: estimating the effect on energy use when building a bypass road

In the debate of climate change and mitigation of greenhouse gases, the issue of energy use is closely related. Several political aims concern the need to reduce the overall energy demand in the society, where transportation is an important contributor. In the transport sector, major efforts have been concentrated on developing more fuel efficient engines and vehicles. However, the road infrastructure, its operation and maintenance also use energy and do have an effect on traffic fuel consumption and emissions. It is therefore important to also take the infrastructure into consideration when addressing the energy issue for traffic and use a broader perspective. The objective of this study is to estimate the total energy use in a life cycle perspective of a road infrastructure investment and the impact of different phases of the roads life time. How the results are related to the transport objectives is also addressed. A life cycle assessment method is used to evaluate an infrastructure investment, including construction, operation, maintenance and traffic during 60 years. A small community is used as a case study where a bypass has been built and the result show that this investment will increase the total energy use by approximately 60%, or 1 550 TJ compared to not building it. A major part of the increase is due to traffic, and since mostly fossil fuel is used there will also be an increase in greenhouse gas emissions. The result stipulates that the aspects of energy efficiency and reduction of greenhouse gases has not been accounted for in the planning or it has been considered as less important than other aspects, e.g. traffic safety and accessibility.