A self-driving taxi operated by Waymo was recently stopped in San Francisco after the company detected what it believed to be an assault rifle inside the vehicle. Waymo has a strict policy prohibiting weapons of any kind in its autonomous vehicles. Last week, two minors were arrested following the incident, which occurred on September 3 in the Outer Richmond neighborhood. A Waymo employee was alerted to the potential presence of a firearm, prompting the company to pull the vehicle over and notify local police. San Francisco Police Department (SFPD) spokesperson Allison Maxie described the stop as a "high-risk vehicle stop," which typically involves situations where law enforcement is concerned about potential danger. When officers arrived at 40th Avenue just before 4 a.m., they searched the car and found an "AR-styled assault rifle also known as a ghost gun," as well as suspected marijuana and mace spray. The two juveniles—identified as one male and one female—were arrested and taken to the Juvenile Justice Center. They are expected to face charges related to illegal firearm possession. The SFPD has not released their names due to their ages. Ghost guns are typically homemade weapons, often made with 3D-printed parts and lacking serial numbers, which makes them harder for law enforcement to track. It is unclear how Waymo detected the weapon in this case, especially given the nature of a ghost gun. This is not the first time Waymo employees have contacted law enforcement about riders in their vehicles. In July, the company reportedly alerted the San Mateo Police Department about two teenagers allegedly drinking alcohol and using water beads in a self-driving car. In that case, Waymo reportedly did not inform the riders that police had been called, instead telling them the car had technical issues before pulling over. The company has not yet responded to requests for comment from The Independent. Waymo, which was founded by Google in 2009 and became an independent company in 2016, has recently expanded its operations to cities like San Diego, Denver, and Tampa. The incident in San Francisco highlights the challenges of enforcing safety policies in autonomous vehicles, where human oversight is limited.