That would essentially be a virtual road train. It's a great solution because you can reduce the distance between the trucks, which improves the fuel efficiency - especially for European-style trucks.

The problem is that they are an absolute nightmare when it comes to highway merging. You really don't want third-parties in-between elements of the convoy, so it essentially becomes a single really long vehicle for merging purposes. On most highways that's simply not a realistic option.

Indeed there are multiple such optimizations. One that occurs to me is a hub/spoke model where inter-city/state is driverless, from/to truck "yards" on the outskirts of cities. Then human drivers take over and drive the last few miles. Drivers get to go home every night and lead normal lives instead of living on the road.

Or a variant of it: as a truck driver, I can « latch onto » a truck in front of me and take a 1h nap.

Would require a virtual handshake between the two drivers, but heck why not esp. if you’re guaranteed that the truck behind you won’t try to pass you for an hour :-)

Or more or less automate the highway so that vehicles share information back and forth. Huge task, but goes a long way towards helping big heavy vehicles have information about what is ahead.