Waymo, the robotaxi company owned by Alphabet, announced today that it is allowing employees and guests to begin traveling in cars powered by its sixth-generation autonomous driving system. Waymo Driver’s most advanced system now runs on its new Ojai robotaxis, built on base vehicles supplied by Chinese automaker Geely.

“This latest system serves as the primary engine for our next period of expansion, with a streamlined configuration that lowers costs while maintaining our uncompromising safety standards,” Waymo Vice President of Engineering Satish Jeyachandran wrote in a blog post.

Waymo says the new system is built with cheaper components and is designed to handle a wider range of environments, including extreme winter weather. The sixth-generation driving system uses updated sensors, including a new high-resolution 17-megapixel imager that captures millions of data points. The company says the improved sensor allows the system to see the vehicle’s surroundings with fewer cameras than needed in low-resolution setups. It also uses cheaper and more efficient lidar and radar sensors.

The system is designed to adapt to different types of vehicles. Currently, that includes the new Ojai taxis and Hyundai Ioniq 5 SUVs. Waymo’s current fleet of Jaguar I-Pace vehicles will still run on its fifth-generation technology; however, the company it received the last shipment of last year’s I-Pace cars.

That said, Waymo said it plans to scale production at its Phoenix factory of its latest self-driving system to tens of thousands of vehicles per year. This is key for the company as it races to expand to more cities this year.

Let’s go now ACTING its robotaxi service in Austin, San Francisco, Phoenix, Atlanta, Los Angeles, and Miami. The company recently said it has plans to expand its service 20 more cities this year, including Tokyo and London.

However, the new update and expansion plans come as the company faces new scrutiny from federal regulators. The National Highway Traffic Safety Administration (NHTSA) recently opened an investigation into an incident in January in which a Waymo robotaxi hit a child near Santa Monica elementary school during drop-off hours. According to Waymo, the car detected the boy as they ran from behind the parked SUV and braked hard, slowing from about 17 miles per hour to less than 6 miles per hour before making contact.

In announcing the investigation, NHTSA’s Office of Defects Investigation said it would examine whether Waymo “exercised reasonable precautions” given the car’s proximity to a school and the presence of young pedestrians. Last month, the agency also launched a separate investigation after reports that Waymo vehicles failed to stop for school buses.