But it also has invited criticism from those who say Pittsburgh is giving too much power to tech companies, all for a sheen of innovation. Some residents are on edge about Uber’s self-driving vehicles and complain that they have been thrust into an experiment with potential safety risks.  “I feel like we were pushed into being part of this by the city,” said Montana Michniak, a recent college graduate who works at a cafe in the city’s South Side neighborhood.  How Pittsburgh handles the unveiling of Uber’s self-driving fleet is being closely watched by other tech and auto companies that are doing their own driverless experiments in places like California and Michigan (although Apple is said to have laid off dozens of employees in its self-driving car project and to be rethinking its strategy). Depressed cities around the nation are watching to see if the Pittsburgh story can be a blueprint for their own transitions into tech hubs.  “This is the first mayor in Pittsburgh to really get it, and that’s a big reason why the city has become the best case of Rust Belt revival,” said Richard Florida, a professor of urban studies at the University of Toronto, who previously taught at Carnegie Mellon University in Pittsburgh. He said he was “frankly surprised at how long a leash” Uber got.  Mr. Peduto said Uber did not have too much power in Pittsburgh and said the city would be safe because there would be a human monitor in the Uber test cars. The mayor also has his eye on a bigger safety goal.  “There is no technology that is fail-proof and there is no tech that can guarantee there won’t be accidents, but right now there are 3,287 people who die in automobile-related accidents around the world each day, and there has to be a better way,” he said.  In a statement, Uber said of Pittsburgh, “Our work would not be possible without the support we’ve received from city leaders.”  Uber came to Pittsburgh in early 2015, drawn by the engineering talent at Carnegie Mellon. The university started a robotics department 30 years ago, when driverless cars seemed like a fantasy, but robotics has since proved crucial for the systems that let vehicles navigate streets on their own.  By this decade, the university’s expertise in computer science had attracted not only Uber but also General Motors, Google and Intel, some of which embedded at Carnegie Mellon. Google and Uber later opened research centers, hiring dozens of Carnegie Mellon professors and graduate students.  Today, Uber has 500 employees at a center in Pittsburgh’s industrial Strip District working on autonomous vehicles, according to Mr. Peduto. Uber will have 1,000 employees at the site, known as the Advanced Technology Center, within a few years and plans to increase investments to $1 billion from hundreds of millions of dollars in a decade, he said.  For driverless car tests, Pennsylvania also held a legal advantage. Specifically, the state’s transportation rules did not explicitly ban driverless cars, as long as someone was behind the wheel to take over if needed.  Officials from Pennsylvania’s transportation agency said they interpreted that silence on driverless technology as a green light. Some state officials said they also believed that driverless cars could be safer than those steered by drivers, helping avoid driver-related deaths.  “We’d be committing governmental malpractice if we didn’t pursue this technology,” said Roger Cohen, the policy director of the Pennsylvania Department of Transportation.  In Pittsburgh, Mr. Peduto fostered a close relationship with Uber. In Mr. Peduto’s first meeting in early 2015 with Uber’s chief executive, Travis Kalanick, Mr. Kalanick said he had noticed efforts by Mr. Peduto and other officials to fight the state public utilities commission’s proposed ban on ride-sharing services like Uber and Lyft in 2014. Mr. Kalanick also laid out a plan for Uber’s driverless cars.  “Travis’s vision was to build out the autonomous vehicles industry in 10 years,” Mr. Peduto said. “We shared a vision to do it in a way that would be a benefit for society.”  Weeks later, in a meeting with President Obama at a conference for the National League of Cities, Mr. Peduto urged Mr. Obama to support autonomous vehicles and declared Pittsburgh’s intention to be a testing ground.  Since then, Pittsburgh has showed its friendliness to Uber’s efforts. Last year, it also worked with the city’s police department on plans to install a ride-hailing kiosk in the lively South Side district, for the use of people who had been drinking and would prefer not to drive home. Pittsburgh International Airport last year also designated waiting areas for Uber and Lyft passengers.  Yet Uber has mostly gone ahead with its self-driving-car plans in Pittsburgh alone. Driverless cars with Uber’s logo have cruised around town for months, in part to get the public used to seeing them. With cameras and GPS units mounted on the roofs, the vehicles collect mapping data on plants and trees, the conditions of sidewalks, and traffic markings for nearly every street.  “There’s really not been a whole lot of collaboration on the actual testing,” said Scott Schubert, Pittsburgh’s assistant chief of police, who rode in one of the Uber vehicles last June and signed a nondisclosure agreement to do so.  Last month, Uber officially announced that the self-driving fleet would go into action in Pittsburgh. Mr. Peduto, who had been informed a few days earlier by Uber, sent a congratulatory text message to Mr. Kalanick. Uber’s chief was in Pittsburgh at the time and invited the mayor to be the city’s first driverless-car passenger.  After the two-mile ride home, Mr. Peduto posted on Twitter that he ended that day as the world’s first mayor chauffeured by an autonomous Uber car.  “I feel fortunate that I have the ear of a C.E.O. of one of the biggest privately held companies,” he said.  An earlier version of this article misstated the surname of the assistant chief of police in Pittsburgh. He is Scott Schubert, not Schuster.  A version of this article appears in print on September 11, 2016, on page A1 of the New York edition with the headline: No Driver? Bring It On. How Pittsburgh Became Uber’s Test City. Order Reprints| Today's Paper|Subscribe
Uber’s experiment with autonomous vehicles is proceeding with the blessing of city officials, who have pretty much just stayed out of the way.