[friendzis]

Equally impressive would be four self driving cars turning left (in right-hand traffic) at equal priority intersection. At least in my country the rules are muddy in this case and no car has explicit priority. The most general "priority in right" loops around and cars should be stuck there indefinitely :)

[tonylemesmer]

I like to imagine to avoid such situations there would some kind of control on the dash that allows a stalemate to be overridden (not the steering wheel :P). It would be great if it were a "give way" button rather than a "I'm going now" button.

[Piskvorrr]

Doesn't matter how the controls look - you can't have the cake of Level 5 autonomy and eat it too by having a human giving control inputs.

(GP: That's actually easy: random exponential binary backoff. It works for other domains quite well.)

[friendzis]

In this particular instance yes, that is easy. The core of the problem is that hard rules force traffic into this deadlock. To avoid this deadlock autonomous vehicles must be taught to sometimes bend the rules. Which brings its own can of worms - how do you teach a robot under what specific circumstances rules can be bent.

[Piskvorrr]

Not a good example - "Yield right _in the order of arrival_" is still a hard rule, but practically deadlock-free.

[dragonwriter]

The rule in California is “first to arrive”, with “yield right” as fallback for simultaneous arrival. Deadlock is unlikely (and a tertiary fallback by compass direction would solve it completely.)