I expect a standard for big-rigs to be developed where there are modular battery compartments on the underside of the trailer for conventional van trailers, such that the truck pulls up, the batteries under the trailer and under the tractor are swapped, and they're on their way again. Depending on how they're designed they might also make for good under-ride protection, so cars can't drive under the trailers and get trapped or crushed.
That will require changes to the load limits in every state, or it won't be accepted by any trucking company. I am not involved in the trucking industry, but I had to load a semi with a bunch of my company's equipment several times. There are laws for loading on each axle, and the truck axle limits are different than the trailer axle limits. And every US state and Canadian province is different. My company's stuff isn't especially heavy but juggling the axle loads is a big pain. Many companies that ship equipment frequently (like my company) have sized their equipment for the max truck loads, based on the weight of the average step-deck trailer and the average truck. If you add even 2000 lb of batteries onto either the truck or the trailer it is going to be a problem for lots of people.