The Trick That Makes Google’s Self-Driving Cars Work – Madrigal – Atlantic: ” Google is engaging in unprecedented, massive, ongoing data collection to transform intractable problems into solvable chores.
The key to Google’s success has been that these cars aren’t forced to process an entire scene from scratch. Instead, their teams travel and map each road that the car will travel. And these are not any old maps. They are not even the rich, road-logic-filled maps of consumer-grade Google Maps.
They’re probably best thought of as ultra-precise digitizations of the physical world, all the way down to tiny details like the position and height of every single curb. A normal digital map would show a road intersection; these maps would have a precision measured in inches.
But the ‘map’ goes beyond what any of us know as a map. ‘Really, [our maps] are any geographic information that we can tell the car in advance to make its job easier,’ explained Andrew Chatham, the Google self-driving car team’s mapping lead.
‘We tell it how high the traffic signals are off the ground, the exact position of the curbs, so the car knows where not to drive,” he said. ‘We’d also include information that you can’t even see like implied speed limits.'”