The city I live in is not flat, nor rectilinear, nor logically arranged. Therefore, algorithmic traffic modelling is hard, statistical models from previous data aren't reliable, and shift happens. I can visualize the way, or the map, but I only have a very general idea which route is least congested now; enter traffic crowdsourcing, and voila...oh wait, it's all congested anyway, as the other Waze users get rerouted to alternates.