Analysis of improvement factors on fuel economy of individual vehicle models using survival analysis

Abstract

In OECD countries, automobile industry has grown very attentive to low emission vehicles. US consumers, who traditionally prefer relatively large cars of good performance, have gradually turned their heads toward more fuel-efficient cars with smaller chassis or alternative fuels. The government departments of developed countries have provided assertive support for environmentally friendly vehicles (low and zero emission vehicles) and restriction on vehicles of poor fuel efficiency. As part of this trend toward sustainable transportation, US Environmental Protection Agency reinforced fuel economy measurement method of newly released vehicles from year 2008. Whereupon, fuel economy of released vehicles after the event diminished in every vehicle model, drastically in some models. After the occurrence of incident, some vehicle models has recovered the fuel economy level before the incident, whereas other models exhibit tendency of remaining in diminished level. This study employs a statistical method, survival analysis, by assigning the time taken from fuel economy diminishment to recovery of previous level as an outcome variable. Furthermore, with survival analysis the effects of technological, societal, and economic covariates on the recovery of fuel economy are analyzed.