Effects of Sustainability Policy – Evaluating Social Consequences of Carbon Targets using Trip Completion Rates

Sustainability is widely recognised as having social, economic, and environmental dimensions. Strategies to combat global climate change inherently have an environmental focus. However, in line with the sustainability agenda, the social and economic dimensions must also be addressed. Evaluating the social consequences of decisions is often challenging due to a lack of relevant tools and indicators to measure and track them. This paper presents the Trip Completion Rate (TCR) as an indicator currently under development to evaluate the social consequences of climate change policies such as Personal Carbon Allowances (PCA). TCR is an accessibility indicator that evaluates the proportion of a population that can perform their daily activities against a performance metric. Two examples demonstrate the sensitivity of social impacts based on the geographic and demographic variations in different locations, one at the region level and another at the municipal level, through a national household travel survey (NHTS). The Västra Götaland region of Sweden is taken as a test case to illustrate how the indicator may be used, comparing TCR on the entire region and then comparing it to TCRs calculated at the municipal level. The greenhouse gas emissions of the trips are calculated based on assumptions for different modes of transport. Finally, the results are evaluated against a hypothetical PCA based on the climate goals for the city of Gothenburg, Sweden. The results show that the ability to satisfy one’s daily travel needs depends on individual characteristics such as behavioural patterns of travel, travel mode choices and access to local amenities. We find that PCAs may disproportionately affect certain groups more than others. Policymakers must understand who is most affected by sustainability targets to ensure that disproportionately affected groups have an equal opportunity to achieve their daily needs and that adequate measures are taken to mitigate the local policy effects on social equity.