Waymo is recalling 3,067 vehicles because of a software issue that led to multiple incidents in which the autonomous cars drove around stopped school buses.

The recall affects certain 5th-generation automated driving systems, according to a Nov. 8 notice posted by the National Highway Traffic Safety Administration (NHTSA). The software may cause vehicles to pass a stopped school bus even when its red lights are flashing or its stop arm is extended, increasing the risk of a crash with a pedestrian, the agency said.

Waymo didn’t immediately respond to a request for comment.

All 50 states have laws requiring vehicles to stop for a school bus with flashing red lights and a deployed stop-arm signal, according to the NHTSA.

Waymo told CBS News last week that it was planning to issue a recall. At the time, a spokesperson said the company had identified the software issue that contributed to the school bus incidents and that it had repaired affected vehicles by Nov. 17.

The recall follows multiple reports that the company’s self-driving cars drove around school buses stopped on the road in Austin, Texas. 

As of Dec. 5, the Austin Independent School District said it was aware of 20 incidents this school year in which a Waymo vehicle illegally passed a school bus. JJ Maldonado, a communications specialist for the school district, told CBS News last week that a 20th citation was issued after Waymo said it had fixed the software issue.

NHTSA launched a probe into Waymo in October after a similar school bus incident in Atlanta. The public school district there said it was aware of six cases as of Dec. 5 in which Waymo cars illegally passed stopped school buses.

Waymo, owned by Google’s parent company Alphabet, offers hundreds of thousands of driverless rides each week in San Francisco, Los Angeles, Austin, Phoenix and Atlanta, and plans to expand to two dozen other cities.