Quantifying transport energy resilience: Active mode accessibility

A reduction in the energy intensity of private transport is the least cost-feasible approach to mitigate the uncertainties of future oil supplies, given the impending peak in world conventional oil production. The built environment and transport infrastructure of an urban form determine the extent to which low-impact adaptations to these constraints are possible and hence the resilience of residents to fuel price shocks and constraints. This paper introduces the concept of active mode accessibility (AMA), defined as the proportion of activities that can be reached by active modes alone, given the population demographics of the study area. AMA is characterized by the underlying geographic form of an urban area and its transport networks. High AMA means that the resident transport activity system can be served with minimal energy input; consequently resilience to fuel shocks and constraints is greater. The AMA method is based on accessibility analysis and extends the depth of the analysis with energy-based activity modeling and defines a measure of energy accessibility. The paper introduces a spatial method for calculating the AMA within a selected study area and a geographic information system-based tool for applying the method, and presents two case studies. Central Christchurch, New Zealand, gives an AMA of 100% because the city has a high density of destinations and a wide range of local facilities available for every activity. The satellite township of Rolleston gives a significantly lower AMA of 59%, principally because of a lack of local preschool and high school facilities and an insufficient diversity of destinations for some activities.