Most of the old trucks have run over 1 million miles, wore out, and were scrapped but the all of the new deisel 18 wheeler trucks can easily be made to run without DEF. Screw the EPA's air polution laws they need to be repealed. Diesel Exhaust Fluid does not make a deisel engine run it just reduces emission but most of the politians don't know that. We all need to contact them and let them know it.