Rafaela Vasquez liked to work nights, alone, buffered from a world she had her reasons to distrust. One Sunday night in March 2018, Uber assigned her the Scottsdale loop. She drove a gray Volvo SUV, rigged up with cameras and lidar sensors, through the company’s garage, past the rows of identical cars, past a poster depicting a driver staring down at a cell phone that warned, “It Can Wait.” The clock ticked past 9:15, and Vasquez reached the route’s entry point. She flipped the Volvo into autonomous mode, and the car navigated itself through a blur of suburban Arizona, past auto dealers and Zorba’s Adult Shop and the check-cashing place and McDonald’s. Then it jagged a short stint through Tempe to start the circuit again. It was a route Vasquez had cruised in autonomy some 70 times before.

As she was finishing her second loop, the Volvo blazed across a bridge strung with bistro lights above Tempe Town Lake. Neon signs on glass office buildings were reflected in the water, displaying the area’s tech hub ambitions—Zenefits, NortonLifeLock, Silicon Valley Bank. Beyond the bridge, the car navigated a soft bend into the shadows under a freeway overpass. At 9:58 pm, it glided to a forlorn stretch of road between a landscaped median and a patch of desert scruff. Four signs in the median warned people not to jaywalk there, directing them to a crosswalk 380 feet away.