California officials are meeting with Tesla on Wednesday "to talk about Tesla's efforts with autonomous trucks," state DMV spokeswoman Jessica Gonzalez said.

The correspondence and meeting show that Tesla is putting self-driving technology into the electric truck it has said it plans to unveil in September, and is advancing toward real-life tests, potentially moving it forward in a highly competitive area of commercial transport also being pursued by Uber Technologies Inc [UBER.UL] and Alphabet Inc's Waymo. 

Musk tweeted in April that the semi-truck would be revealed in September, and repeated that commitment at the company's annual shareholder meeting in June, but he has never mentioned any autonomous-driving capabilities.

"To insure we are on the same page, our primary goal is the ability to operate our prototype test trucks in a continuous manner across the state line and within the States of Nevada and California in a platooning and/or Autonomous mode without having a person in the vehicle," Tesla regulatory official Nasser Zamani wrote to Nevada DMV official April Sanborn. He made no reference to any dates for potential road tests.