Nearly a year ago, Waymo updated its self-driving software and issued a recall after numerous reports that its robotaxis were illegally passing school buses that had stopped and deployed flashing red lights. Now, federal safety regulators have opened a new investigation into why that behavior has continued.

The National Highway Traffic Safety Administration said in a November 6 filing that a majority of these reported incidents occurred after the company deployed a software update intended to fix the problem.

Waymo said last year that a software update was completed for all affected vehicles on November 17, 2025. However, NHTSA said the majority of the incidents occurred after the software update. NHTSA’s Office of Defects Investigation (ODI) has opened a “recall query” to “assess the adequacy of the remedy.”