Tesla Semi travels alone in US with 1609-km 'extension cord'
Tesla CEO Elon Musk has said the startup's autonomous Tesla Semi truck prototype travelled on its own across the US using its existing Supercharger network. Musk further said the truck carried a 1609-km 'extension cord' to help the truck plug in for recharge. He was referring to a system of cords used to charge Semi prototypes at Tesla's charging stations.