[grundleborg]

This problem is an active area of academic research in the transport operations/planning field. It's generally known as "concentration and overreaction".

A classic example would be if a road is severely congested, and satnavs started advising drivers to take an alternative, smaller road, if too many people get the same advice that road will then end up even more congested and delay the people who followed the advice to change routes even more.

http://www.jstor.org/stable/42747332?seq=1#page_scan_tab_con... is a good starting point if you are interested in reading more about this area.

[NeutronBoy]

It's similar to the 'flip-flopping' problem (I'm sure there's a technical term for it) - actions based on feedback from a sensor changing the sensor reading, triggering a different reaction.

A common example I've seen used is: Automatic headlights on a car turning on in the dark. When the headlights turn on when you're in a garage or tunnel, they can create enough ambient light to trick the sensor into thinking it's light, and turning the headlights off. The solution here is to add a delay into the reaction.

I'm wondering what a solution is to a problem with mapping - is it add a delay to re-routing traffic? Or rerouting traffic randomly? Or spread traffic out over a number of routes? It's made harder by the fact that Google in this case won't be routing all traffic - just a subset.