Uber in limited autonomous car tests again in S.F.

FILE - In this March 15, 2017, file photo, a sign marks a pick up point for the Uber car service at LaGuardia Airport in New York. Uber will resume testing autonomous vehicles in an area near Downtown Pittsburgh starting Thursday, Dec. 20, 2018. (AP Photo/Seth Wenig, File) less FILE - In this March 15, 2017, file photo, a sign marks a pick up point for the Uber car service at LaGuardia Airport in New York. Uber will resume testing autonomous vehicles in an area near Downtown ... more Photo: Seth Wenig / Associated Press Photo: Seth Wenig / Associated Press Image 1 of / 1 Caption Close Uber in limited autonomous car tests again in S.F. 1 / 1 Back to Gallery

Uber’s autonomous vehicles returned to public roads in San Francisco, Pittsburgh and Toronto on Thursday, nine months after one of its self-driving cars killed a pedestrian in Arizona.

In San Francisco and Toronto, Uber said, the cars will operate in manual mode, which means a human driver will be in control at all times. Even in Pittsburgh, it will begin with fewer than five cars on the road, and slowly add to that over time.

The vehicles are operating at drastically reduced speeds and in less challenging environments than before, the company said, as it eases back into testing and tries to ensure people’s safety.

MBA BY THE BAY: See how an MBA could change your life with SFGATE's interactive directory of Bay Area programs.

In Pittsburgh, each car will have two drivers inside, ready to take over in case something goes wrong, Uber said. The operators will work in four-hour shifts, down from eight to 10 hours previously. No passengers will ride in the cars.

The autonomous cars will also go no faster than 25 mph, down from as fast as 55 mph before. They will operate only on a limited loop in Pittsburgh’s Strip District, a bustling commercial area, and only during daylight hours on weekdays, Uber said.

The San Francisco tests will be primarily around Uber’s Pier 70 engineering center, with cars hitting the street in the Mission District and the South of Market, Potrero Hill, Dogpatch and India Basin areas. Vehicles may also be driven for repositioning, including to a test track in Concord.

Vehicles will be driven during daylight hours and travel at the posted speed limit. The lidar units atop the cars will be spinning, but purely for data collection, Uber said, and the vehicles will not be capable of self-driving operation.

The company has informed the Department of Motor Vehicles and San Francisco Municipal Transportation Agency of the testing plans.

“We will continue to prioritize safety,” Eric Meyhofer, who leads Uber’s autonomous vehicle unit, said in a statement.

The company had grounded its fleet of autonomous vehicles in March after one of its cars — with a distracted backup driver behind the wheel — struck and killed Elaine Herzberg, 49, on a street in Tempe, Ariz.

Getting the cars back on the road since then has been difficult. As Uber worked to make its cars safer, it lowered its expectations for speed and performance, the New York Times reported. Even so, the cars struggled to pass safety tests. Last month, the cars were still failing 10 out of 70 safety tests, according to internal documents.

The safety overhaul “required a lot of introspection and took some time,” Meyhofer said. “Now we are ready to move forward.”

Uber’s autonomous vehicle group most likely will face intense scrutiny over the next several months. The National Transportation Safety Board’s investigation into the Arizona crash is still open.

Uber has pitched autonomous vehicles as a way to reduce the fees it pays to human drivers. But the company is still spending heavily on developing and testing the cars. CEO Dara Khosrowshahi has been focused on winnowing unprofitable businesses ahead of taking the company public next year.

San Francisco Chronicle staff contributed to this report.

Kate Conger is a New York Times writer.