Comment by jjav
17 hours ago
There aren't infinitely many scenarios to consider, but even if that's a figure of speech, there aren't thousands or even hundreds.
If there's ten kids nearby, that's basically ten path scenarios, and that might be reduced if you have great visibility into some of them.
> My brain might be able to quickly assess a handful, but certainly not all.
What would you do if you can't assess all of them? Just keep driving same speed?
If the situation is too overwhelming you'll almost certainly back off, I know I would. If I'm approaching that school block and there's like 50 small kids running around in all directions, I have no idea what's going on and who is going where, so I'm going to just stop entirely until I can make some sense of it.
It should be trivial for Waymo to implement a "drive carefully near schools" feature, and if really spicy "drive REALLY carefully near schools at these times" feature.
Safe driving starts with speed, lowering speed and informing the passengers seems like a no-brainer.
Feels like bitter lesson fodder to special case things like this
> here aren't infinitely many scenarios to consider, but even if that's a figure of speech, there aren't thousands or even hundreds.
There are a very, very large number of scenarios. Every single possible different state the robot can perceive, and every possible near future they can be projected to.
Ten kids is not 10 path scenarios. Every kid could do a vast number of different things, and each additional kid raises the number of joint states to another power.
This is trivially true. The game that makes driving possible for humans and robots is that all these scenarios are not equally likely.
But even with that insight, it’s not easy. Consider a simple case of three cars about to arrive at an all-way stop. Tiny differences in their acceleration - potentially smaller differences than the robot can measure - will result in a different ordering of cars taking turns through the intersection.
It’s a really interesting problem.
> Ten kids is not 10 path scenarios. Every kid could do a vast number of different things, and each additional kid raises the number of joint states to another power.
This is the difference between computing and humans. The car will attempt to compute all possible path scenarios because it has no instict, and it might not be possible to compute everything in real time so it might fail.
But the human will easily deal with the situation.
Try running through a sports field in an elementary school during lunch, full of unpredictable kids running around. Can you make it from one side to the other without crashing into a whole bunch of kids? Of course you can. You didn't need to try to compute an exponential number of scenarios, you just do it easily. The human brain is pretty amazing.
It was a figure of speech, but I think you're undercounting. When you consider interactions between all the things, even with just a handful of variables (and I think there are many more than a handful) you get a huge number of scenarios.