https://www.cnet.com/roadshow/news/2018-epa-wheeler-glider-truck-regulations-enforced/

The Obama administration sought to close the loopholes that allow gliders to be built and sold in significant numbers in an effort to curb their pollution but Pruitt opted to toss that aside in the name of business. We've covered the glider situation in the past, but the big news is that the new acting head of the EPA, a former coal lobbyist, has moved to reinstate the Obama regulations after a court insisted that they be enforced once again.

Gliders are new truck chassis and bodies that are powered by older, less emission-controlled engines.