In many countries, vehicle replacement policies are implemented to reduce the average age of the vehicles on the road. Through these policies, policymakers typically aim to reduce emissions and to stimulate demand for automobiles through vehicle renewal. Not much is known however, about the more detailed operational consequences of vehicle age in truck transportation. In this study, we empirically address this issue by analyzing data obtained from 27 thousand trips made by 916 drivers in 355 unique trucks, over a period of 346 days. Using this data, we test the relationship between truck age and driver retention, productivity, and unsafe driving behavior. Our results demonstrate that truck age significantly impacts driver turnover, with every additional year of truck age relating to an approximate 5% higher risk of leaving the job at a given point in time. Contrarily, drivers with older trucks drove significantly less volatile, which suggests that they drive more safely. The results illustrate that vehicle age influences a broader spectrum of outcome measures than typically considered when assessing the expected impact of replacement policies. Policymakers and trucking companies can use these results to make more informed decisions about vehicle replacement, thereby also addressing the widespread issue of driver shortage.