Back when I worked on self driving cars we called it the cliff problem. It's pretty straightforward to spot things that are in your way (trees, cones, broken do

Back when I worked on self driving cars we called it the cliff problem. It's pretty straightforward to spot things that are in your way (trees, cones, broken down car) using LIDAR. It's really hard to notice when a road abruptly ends. From the perspective of the cars' LIDAR a roll over and a sheer cliff look pretty similar. Either way you just won't hit any targets at all with the laser beam. There was a silly obstacle on many self driving car courses that basically had the car drive up and over a relatively steep bump. At the crest of the hill the cliff detection would usually trigger and a lot of cars would just pause there, the roll over looked like a sheer cliff when the car was at a 15 degree up angle. I assume we can make it work with computer vision for much the same reason humans don't routinely (though sometimes) drive off cliffs.