A Waymo robotaxi was recently spotted driving around a school bus that had its red lights flashing, and federal safety regulators have opened an investigation as a result.

The National Highway Traffic Safety Administration (NHTSA) announced Monday morning that its Office of Defects Investigation (ODI) opened an investigation after seeing footage from early October of a Waymo autonomous vehicle maneuvering around a stopped school bus that was unloading kids in Atlanta, Georgia.

ODI says in a document that it will investigate the performance of Waymo’s self-driving software around stopped school buses, how the system is designed to comply with rules related to the buses, and more. The NHTSA said Monday that, based on its engagement with Waymo so far, the “likelihood of other prior similar incidents is high.”

The Waymo robotaxi in question crossed perpendicularly in front of the school bus from its right side. The autonomous vehicle then turned left around the front of the bus before traveling down the street. According to Waymo, the bus was partially blocking the driveway that the robotaxi was leaving. The company claims the robotaxi could not see the flashing lights or stop sign. Waymo did not immediately respond to a question about whether the vehicle could see the students getting off the bus, or the bus’s control arm.

“Safety is our top priority, as we provide hundreds of thousands of fully autonomous paid trips every week in some of the most challenging driving environments in the U.S.,” the company said in a statement, while citing data that shows its vehicles get in fewer crashes than human-driven ones. “NHTSA plays a vital role in road safety, and we will continue to work collaboratively with the agency as part of our mission to be the world’s most trusted driver.”

Waymo also said Monday that it has already issued software updates to its fleet to improve performance.

This has been a year of expansion for Waymo. The company launched in Atlanta, brought its robotaxis to Austin, expanded across Silicon Valley, and is testing in a number of other metro areas, including New York City. It’s also testing at the San Jose and San Francisco airports, and has many more cities lined up for 2026.

Part of the process of launching in new cities is having the self-driving system encounter and learn from new scenarios — although it’s safe to say Atlanta was not the first place that Waymo’s robotaxis have seen school buses.

This is not the first time the NHTSA has opened an investigation into Waymo’s self-driving cars. In 2023, the NHTSA probed reports that Waymo’s vehicles were struggling with roadway barriers like gates and chains in low-speed situations. That investigation ultimately led to a recall back in May, which Waymo addressed with a software update. Last year, the agency announced a probe centered on reports that Waymo vehicles had driven into the wrong lane or entered construction zones.