Federal safety regulators have discovered nine more incidents that raise questions about the safety of Waymo’s self-driving vehicles operating in Phoenix and San Francisco. 

The National Highway Traffic Safety Administration Office of Defects Investigation (ODI) opened an investigation earlier this month into Waymo’s autonomous vehicle software after receiving 22 reports of robotaxis making unexpected moves that led to crashes and potentially violated traffic safety laws. The investigation, which has been designated a “preliminary evaluation,” is examining the software and its ability to avoid collisions with stationary objects and how well it detects and responds to “traffic safety control devices” like cones.

The agency said Friday it has added another nine incidents since the investigation was opened. Waymo could not be reached for comment; TechCrunch will update the article if the Alphabet-owned company responds.

Waymo reported some of these incidents. The others were discovered by regulators via public postings on social media and forums like Reddit, YouTube and X. The additional nine incidents include reports of Waymo robotaxis colliding with gates, utility poles, and parked vehicles, driving in the wrong lane with nearby oncoming traffic and into construction zones. 

The ODI said it’s concerned the robotaxis “exhibiting such unexpected driving behaviors may increase the risk of crash, property damage, and injury.” The agency said that while it’s not aware of any injuries from these incidents, several involved collisions with visible objects that “a competent driver would be expected to avoid.” The agency also expressed concern that some of these occurred near pedestrians. 

NHTSA has given Waymo until June 11 to respond to a series of questions regarding the investigation.

NHTSA has stepped up its inquiries into automated driving technology. Earlier this month, the agency opened an investigation into autonomous vehicles operated by Amazon-backed Zoox. The investigation was triggered after receiving two reports of the company’s autonomous-equipped Toyota Highlanders being rear-ended by motorcycles after the SUVs unexpectedly triggered the brakes.