The top U.S. road-safety regulator is gathering information about a Tesla Inc. feature that allows customers to remotely call for their car to pick them up.

The National Highway Traffic Safety Administration is aware of reports related to Summon, a feature the electric-car maker made available last week, and is in ongoing contact with the company, according to an emailed statement. The agency said it “will not hesitate to act” if it finds evidence of a safety-related defect.

Tesla drivers have flooded social media with videos of themselves trying out Summon. The feature enables owners to use the Tesla app on their smartphone to remotely direct their car to pilot out of parking spaces and navigate their way to them. Some customers have praised the feature, but others have posted footage showing their cars getting into scrapes with other vehicles or narrowly avoiding accidents.

NHTSA has taken a hands-off approach to automated driving systems by opting not to issue new regulations for the technology. Instead, U.S. Transportation Department regulators have issued voluntary guidelines for manufacturers to consider, in part to avoid erecting potential barriers to development and testing.

Under NHTSA safety rules, companies don’t need permission from the agency to introduce new systems on vehicles that otherwise comply with federal auto safety standards. That applies even for newer systems that automate part of the driving task, such as automatic emergency braking. If NHTSA finds a system presents an unreasonable safety risk, it can exercise its recall authority.

In Tesla’s home state of California, the Department of Motor Vehicles concluded that Summon doesn’t meet its definition of autonomous technology, meaning it isn’t subject to the agency’s self-driving regulations.

“Tesla does not need a permit to deploy the feature in California,” Marty Greenstein, a spokesman for the department, said in an email. “As with any new technology, the DMV indicated to Tesla that clear and effective communication to the driver about the technology’s capabilities and intended use is necessary.”

Tesla has said on its website that owners are required to monitor their vehicle while the feature is in use. Customers also are supposed to be ready to stop the vehicle at any time, either by using Tesla’s app or pressing a button on their key fob or door handle.

Representatives for Tesla didn’t respond to a request for comment on NHTSA’s information gathering. Chief Executive Officer Elon Musk tweeted Sept. 30 that Summon was “probably our most viral feature ever.”

Hours after NHTSA issued its statement, Musk posted that the feature has already been used more than 550,000 times.

(Updates with NHTSTA background starting in the fourth paragraph.)

–With assistance from Ryan Beene.