Self-driving Waymo taxis have gone viral for negative reasons including the death of a beloved San Francisco bodega cat and pulling an illegal U-turn in front of police, who were unable to issue a ticket to a nonexistent driver.

But this week, the company behind the self-driving taxis is drawing attention to the happier news that a San Francisco woman gave birth in a Waymo.

The woman was on her way to the University of California, San Francisco medical center Monday when she delivered inside the robotaxi, said a Waymo spokesperson in a statement Wednesday. The company said its rider support team detected “unusual activity” inside the vehicle and called to check on the rider as well as alert 911.

Waymo, which is owned by Google’s parent company, Alphabet, declined to elaborate on how the vehicle knew something was amiss.

The taxi and its passengers arrived safely at the hospital ahead of emergency services. Jess Berthold, a UCSF spokesperson, confirmed the mother and child had been brought to the hospital. She said the mother was not available for interviews.

Waymo said the vehicle was taken out of service for cleaning after the ride. While still rare, this was not the first baby delivered in one of its taxis, the company said.

“We’re proud to be a trusted ride for moments big and small, serving riders from just seconds old to many years young,” the company said.

The driverless taxis have surged in popularity even as they court higher scrutiny. Riders can take them on freeways and interstates around San Francisco, Silicon Valley, Los Angeles and Phoenix, Arizona.

In September, a Waymo pulled a U-turn in front of a sign telling drivers not to do so, and social media users criticized police in San Bruno, California, because state law prohibited officers from ticketing the car. In October, a popular tabby cat named Kit Kat, known to pad around its Mission District neighborhood of San Francisco, was crushed to death by a Waymo.