Greening the fleet: A spatial analysis of the local and global emission factors of the car fleet of the United Kingdom

Morton, Craig; Anable, Jillian; Wadud, Zia; Chatterton, Tim

Abstract

This paper provides a spatial comparison of the carbon dioxide (mean grams of CO2 per kilometre) and the nitrogen oxide (mean grams of NOx per kilometre) emissions factors of the car fleets registered across the local authorities of the United Kingdom as of 2014. These metrics are derived from the New European Driving Cycle test procedure and provide an indication of the global and local pollution profiles of the local car stock. Exploratory spatial analysis indicates that these emission factors exhibit a substantial geographical variation across the local authorities, suggesting that some local car fleets are dirtier or cleaner than others. Spatial autocorrelation analysis indicates that a significant degree of spatial organisation in these emission factors is present, with a number of hot-spots and cold-spots identified. Interestingly, these emission factors are uncorrelated with one another, suggesting that they represent separate perspectives on the environmental sustainability of the local car fleet. A series of ordinary least squares and spatial regression models are specified which partially explain the variation in both the emission factors. These models utilise ancillary attributes of the car fleet, the socioeconomic characteristics of the population and the features of the application environments as explanatory variables to determine how local contexts condition these metrics. The results of the models identify a complex set of associations between these different variable categories, with certain variables both promoting and hindering improvements in the car emission factors. These results might prove of use in the formation of policy initiatives to mitigate emissions of these compounds from car use, illustrating that the pursuit of these two objectives may require alternative strategies in terms of car fleet management.

• Presentation Conference Type: Conference Paper (unpublished)
• Conference Name: 49th University Transport Studies Group Conference
• Start Date: Jan 4, 2017
• End Date: Jan 6, 2017
• Acceptance Date: Nov 30, 2016
• Publication Date: Jan 6, 2017
• Peer Reviewed: Not Peer Reviewed
• Keywords: emissions
• Public URL: https://uwe-repository.worktribe.com/output/900223
• Publisher URL: http://www.utsg.net/web/index.php?page=annual-conference
• Additional Information: Title of Conference or Conference Proceedings : 49th University Transport Studies Group Conference