The technology that enables autonomous vehicles is developing so quickly that self-driving trucks could be ready to cruise down interstate highways by 2025, but legislation and regulatory issues will likely slow that release down significantly, according to a panel held Tuesday at the CSCMP EDGE 2019 annual meeting in Anaheim.

The specific timing of approval for autonomous operation in freight "strongly depends on legislation," Stephan Keese, a senior partner at Roland Berger LLC, said in a CSCMP session called "The Driving Force Behind Autonomous Fleets."

Despite those challenges, investors are rushing to pump money into the sector, as evidenced by the news Tuesday that San Diego-based autonomous driving tech vendor TuSimple had raised $215 million in "Series D" venture capital funding. The money came from SINA, a division of social media platform Weibo, as well as the logistics and transportation giant UPS Inc., CDH Investments, and tier-one automotive supplier Mando Corp.

The investment brings TuSimple's total funding to $298 million to date, and will be used to expand long-haul service for fleets and to co-develop a commercial self-driving truck with OEMs and Tier 1 suppliers, the company said.

TuSimple has already begun hauling commercial loads on U.S. highways in Arizona, New Mexico, and Texas for clients including the U.S. Postal Service, according to TuSimple's head of public and government affairs, Robert Brown. However, the company is not planning to expand those routes anytime soon, since the rules and regulations for self-driving trucks in the other 48 contiguous states look like a patchwork quilt of various conditions, Brown said in the session.