Reply #7: They do

[aePrime]

They do, but this was just an example of a problem that we can't solve efficiently right now. If somebody proved P = NP, we could potentially solve this problem very easily.

The right-turn rule is orthogonal to the problem I was trying to illustrate. If we drove on the left side of the road, they'd have a left-hand rule, as it's just a condition of traffic flow/ traffic laws, and not related to the shortest route. In short, imagine you had the roads all to yourself... . :)