- NTSB Chairwoman Jennifer Homendy called the company's use of "Full Self-Driving" for its latest driver-assist systems "misleading."
- The comments come a day she sent a letter to Tesla CEO Elon Musk about the company not responding to recommendations issued by the safety watchdog four years ago.
- The letter as well as other safety probes into Tesla crashes by the National Highway Traffic Safety Administration have had little impact on the company's stock price.
The head of the U.S. National Transportation Safety Board on Tuesday doubled down on criticisms of Tesla's driver-assist systems following several fatal crashes in recent years, calling the company's use of "Full Self-Driving" for its latest systems "misleading."
The comments come a day after NTSB Chairwoman Jennifer Homendy sent a letter to Tesla CEO Elon Musk about the company's failure to respond to recommendations issued by the safety watchdog four years ago to limit the system's functionality and implement more stringent safeguards to monitor driver disengagement.
"It's clear that if you're marketing something as full self-driving and it is not full self-driving, and people are misusing the vehicles and the technology, but you have a design flaw and you have to prevent that misuse," Homendy said on CNBC's "Squawk Box." "And part of that is how you talk about your technology. It is not full self-driving. ... It's misleading."
Homendy said Tesla has not yet officially responded to the NTSB regarding its safety recommendations. She also said she has not met Musk, but she has visited Tesla's plant in California and has driven a vehicle with Autopilot, offered by Tesla.
The letter as well as other safety probes into Tesla crashes by the National Highway Traffic Safety Administration have had little impact on the company's stock price. On Monday, Tesla's market value hit $1 trillion. The stock closed Monday up by 12.66% at about $1,024 a share.
The NTSB currently has 10 investigations into Tesla fires and crashes, Homendy said Tuesday. Three or four are open investigations, she said.
Tesla's driver-assistance systems are marketed as Autopilot, Full Self-Driving and FSD Beta in the U.S. However, Tesla does not make self-driving cars, and the company warns drivers in owners' manuals to keep their hands on the wheel and "be prepared to take over at any moment."
Full Self-Driving is marketed with the promise of enabling a Tesla to automatically change lanes, navigate on the highway, and move into or roll out of a parking spot. FSD Beta gives drivers a chance to test an unfinished "autosteer on city streets" feature, which enables them to automatically navigate around surface streets and urban environments without moving the steering wheel with their own hands.
"My biggest concern is that Tesla is rolling out full self-driving technology in beta on city streets with untrained drivers and they have not addressed our recommendations that we've issued as a result of numerous investigations of Tesla crashes," Homendy said Tuesday.
Homendy's criticisms follow Tesla identifying issues with its latest update, called Full Self-Driving Beta v.10.3, over the weekend and it scrambled to revise it after its initial release.
The NTSB does not have regulatory authority like the National Highway Traffic Safety Administration. It is an independent federal agency charged by Congress with investigating civil aviation accidents in the U.S. and significant accidents in other modes of transportation such as automotive. It then recommends actions for companies to take to avoid future accidents.
Tesla did not respond to a request for comment.
— CNBC's Lora Kolodny contributed to this report.