In fact, as Elon Musk said, the semitrailer has been traveling thousands of kilometers on its own during the last weeks. It does not mean only that it has not been driven by any human, but that it has not been escorted by any vehicle, as it had been in previous tests.
What’s cool is that it was driven across the country alone (not escort or any accompanying vehicles), using the existing Tesla Supercharger network and an extension cord
– Elon Musk (@elonmusk) August 25, 2018
It has only required human assistance when it comes to connecting to the superchargers, something that it can not do without an extension cable and a human, until now. These superchargers are points with ultra-fast chargers capable of charging the truck’s battery in a short time (to continue the journey as soon as possible), and the Semi Truck connects to several of them at the same time.
Recall that, in reality, the Tesla truck is designed to operate autonomously in a Megacharger, not in a Supercharger, but for the moment the Semi Truck loaders are not yet available (hence it is connected to several superchargers at Same time). The charging stations originally designed for the truck will provide enough energy in half an hour to cover 463 kilometers.