The National Highway Traffic Safety Administration (NHTSA) has closed its 14-month investigation into a series of crashes involving self-driving Waymo vehicles, Reuters reports.

The probe examined 22 incidents involving 440 Waymo vehicles, including 17 collisions. Some of the cases involved the autonomous vehicles disobeying traffic control devices or exhibiting “unexpected behavior" near these devices. None of the incidents are known to have resulted in injuries.

The investigation had major knock-on effects for Waymo. The Alphabet-owned company recalled 1,212 of its robotaxis in May, chalking up the incidents to a software glitch. Waymo’s May recall included a software update meant to improve detection and avoidance of roadway barriers such as chains and gates.

The agency cited Waymo’s recalls and its analysis of available data in closing the investigation, including a 672-vehicle 2024 recall after one of its robotaxis collided with a wooden utility pole in Arizona.

Recommended by Our Editors

Waymo Halts Freeway Operations, Stops Service in Some Cities Without Clearly Communicating What's Up

Waymos Get Way More Roomy With the Addition of Spacious Minivans to Its Robotaxi Fleet

Tesla Recalls Over 14,500 Model Y Cars to Check for a Missing Weight Label

“At Waymo we are committed to prioritizing safety and we’re pleased that NHTSA has concluded their investigation and closed our case,” a Waymo spokesperson said on Friday.

The news comes as Waymo’s services are continuing to slowly expand across the US. Waymo rides became available via the Uber app in Atlanta in June, after rolling out in Austin in March. The company also operates in Phoenix, Los Angeles, and San Francisco. Meanwhile, its robotaxis began testing in Philadelphia earlier this July, as the company also commenced its second round of testing in New York City. It also picked up a hefty $5.6 billion funding round in late 2024 to fuel its roll-out into new markets.

But while Waymo has certainly racked up some wins in recent months, opposition is mounting across parts of the US amid its expansion. Earlier this week, protesters gathered outside Boston City Hall to highlight the potential risks of driverless vehicles ahead of a City Council committee meeting on autonomous vehicle operations, according to The Boston Globe.