ponytug
Super Member
I'm not sure that would fly around here.
With the caveat that while many states follow the Federal rules, here are a few Federal regulations that apply for interstate transport.
Around here, the highway patrol follows the Federal regulations, although I haven't put it to the test personally.
There must be a DOT plate fastened to the tank by the manufacturer, and the metal tank must be "permanently secured to a transport vehicle" per the Federal DOT. (CFR 49 & 173.8(c)) The flashpoint of the fuel must be more than 100F, I.e. diesel.
Each tank has to be less than 119 gallons (450L), and a maximum of less than 1,000 gallons total on a vehicle. Anything more requires a HAZMAT endorsement on the driver's license and binding/insurance.
There are state rules here that require plastic fuel tanks to be filled on the ground. Gasoline tanks can be 5 gallons, and must be secured in a pickup bed.
That's not to say I haven't seen folks not adhering to the regulations, but none of my local stations allow large plastic tanks to be filled. Then again, the only off-road diesel stations are a ways away, and require a fuel card with monthly minimum purchases. (Which I don't meet.)
All the best,
Peter