Have you heard of “gliders?” No, not the aircraft towed to high altitude to ride updrafts and later land. Today, gliders are new trucks less drivetrain that use a loophole in the EPA rules that allow them to install an older, less environmentally friendly engine. The big tractor brands, Kenworth, Peterbilt and Freightliner, all sell new chassis sans drivetrain. After a rebuilt engine circa 1998-2002 has been installed, it is considered a new truck that is not EPA particulate restricted and is therefore more efficient but dirty. How dirty? Fifty-five times more particles emitted and up to 43 ti...