I know that there are Transports built that are not built to ASME codes. Some are vessels for Hazardous waste where pressures are not above 5 psi and no Vacuume. These, however, are built to DOT Specifications and call for ASME design data, but without the requirnment for ASME documentation. I'm not talking about these. Some are built the same way, but have an oilfield exemption. I'm not refering to these. What I mean are those out there that have been built for hauling water or any other commodity concedered non-hazardous.

What standards are these built to? Who is the authority that allows these on the highways? Are they just required to meet the DOT standards for safety & construction that any other highway trailer would be?

Thanks for your candid opinions in advance.