Interesting - I noticed recently, for the first time, that when I modified a 'fastest' proposed route using local knowledge, I found the predicted time dropped,

Interesting - I noticed recently, for the first time, that when I modified a 'fastest' proposed route using local knowledge, I found the predicted time dropped, and that has happened several time since. This may be the result of better predictive modeling, and particularly in recognizing that dumping a lot of traffic into a low-capacity route is pointless. It is probably also a political response to the fact that residential areas don't like having a lot of traffic routed through them, and are pressing for the power to regulate it. Better predictions could also explain toast0's observations even when global optimization is not being attempted.