Hmmm, I'm not sure the equation is so obvious.

If you don't have a driver, then the vehicle amounts to just a couple motors, batteries, and sensor arrays.

It doesn't make a difference if the battery is located in the front "truck" part of the convoy, or whether it's distributed throughout the trailers.

For a very long chain of trailers, you probably want a set of motors for every trailer right?

And as you've speculated, there's going to be a sensor array in every trailer.

So basically, you have motors in every trailer, batteries in every trailer, and sensors in every trailer. At that point ... why do you need a "truck" on the front and/or why are they connected at all?