Self-driving cars need test miles to prove safety

In early August, ride-hailing service Uber said it would buy Otto, a tech startup that makes self-driving trucks.

And last week, Uber said it will put a fleet of 100 self-driving cars for hire on Pittsburgh streets by month’s end.

The moves mean that the streets of a large American city, one that gets an average of 41 inches of annual snowfall and has more than 400 bridges, will become the company’s laboratory. And the test subjects will be real people who summon the vehicles, some weighing more than two tons with turbocharged engines, with their smartphones.

Autonomous vehicles represent the future of transportation, industry officials say, with the potential to cut down on accidents and fill in gaps in public transportation. Perfecting the technology is a top priority for companies such as Google and Apple and automakers such as General Motors.