'Ask a futurist about self-driving cars, and you’ll hear an exciting story: traffic that flows like clockwork, pedestrians stepping into the street without fear, and collisions so rare they make the news. That story will probably come true, eventually. But to get there, we will have to pass through a long stretch—perhaps lasting decades—with road conditions worse than they are today. The outcome will be a future so much better than today’s that human driving won’t seem outdated; it will seem unthinkable.

For now, as San Francisco learned, even good conditions can produce strange gridlock. Last year a Waymo robo-taxi sat motionless behind a double-parked delivery van. Any human driver would have nudged forward, checked for oncoming cars and slipped past. The Waymo began to do that but encountered another Waymo coming the other way. Each stopped to let the other proceed. Neither did. Behind them drivers honked, and more Waymos arrived, which also waited. Finally, after about four minutes, the second Waymo crept free, ending the gridlock.

That standoff captures the challenge of automated-driving technology. The result won’t be the mayhem and catastrophe that many fear when they think of driverless cars, but rather a pervasive drag: slower flow, more near-misses and a growing sense that nobody is in charge.'

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