Driving propensity and vehicle lifetime mileage: A quantile regression approach

This study aims to determine the relationship between motor vehicle lifetime and lifetime mileage, while considering drivers' propensity to drive and its effects on vehicle CO₂ emissions. To do this, we analyze the relationship between lifetime mileage and vehicle lifetime for two vehicle types; a hybrid and a gasoline vehicle. We also employ a quantile regression approach to estimate the effects of drivers' propensity to drive on lifetime mileage. By estimating the CO₂ emissions based on driver's propensity to drive, we analyze the effects of propensity to drive on vehicle CO₂ emissions. Our results show that, for drivers who drive longer distances, the rate of decrease in average mileage grows as the vehicle age increases. Further, the results of our analysis, which considers this decrease in mileage, show that the cumulative CO₂ emissions calculated under the assumption of uniform average annual mileage have been overestimated. The actual lifecycle CO₂ emissions for the Prius are therefore smaller than previously reported by the previous studies, leading us to conclude that the hybrid is a more environmentally friendly vehicle than previously thought. Those of the Premio as a conventional gasoline vehicle, however, is approximately twice that. We suggest that vehicle lifecycle assessments should take into account the annual decrease in mileage demonstrated in this study.