All new trucks use DEF and burn low-sulfur diesel since California requires it. That has been the case for at least 10 years, if not more. The only trucks on th

All new trucks use DEF and burn low-sulfur diesel since California requires it. That has been the case for at least 10 years, if not more. The only trucks on the road that do not are older trucks and some "gliders" (new chassis and body with an overhauled engine that is older and doesn't have to meet the regulations). The vast majority of big trucks run cleaner than cars or pickups. By the way, trucking is one of the most highly regulated industries.