The National Transportation Safety Board (NTSB) is pushing for the U.S. government to impose stronger requirements for the design and rollout of automated driving systems, citing confusion over Tesla's (TSLA 11.37%) Autopilot as an example of why tighter requirements are needed.

The NTSB, in a comment letter to the National Highway Traffic Safety Administration (NHTSA), cited Tesla's willingness to test unproven software on public roads as proof that rules need to be clarified and tightened. The letter, dated Feb. 1, was first reported by CNBC on Friday.

The NTSB letter said in part: "Tesla is testing on public roads a highly automated [autonomous vehicle] technology but with limited oversight or reporting requirements. Although Tesla includes a disclaimer that 'currently enabled features require active driver supervision and do not make the vehicle autonomous,' NHTSA's hands-off approach to oversight of AV testing poses a potential risk to motorists and other road users."

Tesla's marketing of its Autopilot features has long been a target of critics. The company sells a $10,000 package it markets as "full self-driving," though the vehicle manual stresses the systems should not be deployed without the driver remaining vigilant.

A Tesla Model Y.

Image source: Tesla.

Autonomous vehicles and electrification are the two biggest trends in the auto industry right now, and clear rules would help determine the abilities and limits of not just Tesla vehicles but developments from other automakers as well. Currently the federal government mostly leaves the job of writing autonomous-driving guidelines to the states.

The NTSB and NHTSA are both part of the U.S. Department of Transportation. The NTSB is charged with investigating accidents and potential defects, while the NHTSA is responsible for mandating vehicle recalls and publishing standards.

In separate news Friday, Tesla was sued by an investor claiming that CEO Elon Musk has exposed the company to billions in potential liability and market losses due to his continued "erratic" tweets. In 2018, Musk reached a settlement with the Securities and Exchange Commission calling for the company to adopt strict oversight procedures to govern his social media activity. But the suit claims Musk has continued to tweet with little to no apparent oversight.

The suit cites Musk's May 2020 post that suggested Tesla shares were overpriced as one example of his questionable conduct.