Now, let's say that the 200 car/min turns to a bottleneck of 100 car/min if it's overwhelmed 10 mins downstream of the turnoff. If google routes >200 car/min to the turnoff, there will eventually be a significant traffic jam: cars will pile up at the bottleneck, and even if waze stops routing to the turnoff at that point, the jam would still travel upwards like a pressure wave until it hits the turnoff.
I'd have a hard time believing it's possible for waze to know beforehand what those throughputs are, so some situations like this must occur.
Is there any competitor I can check to confirm best routes?
Take the toy example illustrating that paradox ( https://en.wikipedia.org/wiki/Braess%27s_paradox#Mathematica... ) and an enlightened Google maps may do the altruistic thing of telling half of the drivers to stick on the upper route and half of the drivers to stick to the bottom route, but then some 3rd-party app will come along with the "shortcut" down the middle.
Let's say enough cars take the suggestion to slow down that route by 10 minutes and speed up this one by 10 minutes. Even if you end up saving five minutes relative to the original estimate, you'd have saved ten minutes staying put.
Various cities round the world have different optimization goals as they try out different approaches.
what portion of all the other driver's around me also looking at google maps? Is Google Maps telling them to take the same alternate route as me? Are they all going to do it? If they all do it, does the alternate route (which likely can't handle as much traffic as the original route) just became as jammed as waiting in traffic? Or even worse, if they're all going to do what google maps says, would I in fact be much better off ignoring it and sticking to the original route?
It's hard to tell what's imagination/selection bias, but following google maps traffic-jam-avoidance suggestions has seemed disastrous enough to me enough times that I mostly just stick to the original route now. (Of course, one could also imagine using one's own route knowledge to pick an alternate route of one's own without google maps...)
I suppose google maps could be smart enough to tell half the people to go one way and half the other... I kind of doubt it is, but one could imagine a computerized route direction system which, if enough driver's had it, could actually maximize efficiency by sending different drivers different routes intentionally... I'm not holding my breath for it.