Traversing a rectangle of grass at 2mph in a backyard is absurdly simpler than self-driving cars on open roads, and the absolute worst-case is something like a

Traversing a rectangle of grass at 2mph in a backyard is absurdly simpler than self-driving cars on open roads, and the absolute worst-case is something like a foot or pet injury. There are multiple companies that already sell automatic lawn mowers in the $1000+ range. Some you bury a boundary wire around the target area, others figure it out with cameras.