Waze and other traffic dodging apps prompt cities to game the algorithms

A sign used in Fremont, Calif. to warn drivers that no left turns will be allowed from 3:00 - 7:00 pm, to keep people from taking shortcuts through the town. It warns people not to trust their mapping apps. Smartphone apps like Waze, a godsend for some road warriors because they shave minutes and even hours off their commutes with their creative detours off main highways, are causing headaches for city planners. Using crosswalks, wider sidewalks and traffic lights, these transportation engineers aim to make neighborhood traffic slow, safe, and friendly for pedestrians -- not send frustrated commuters barreling down side roads. But the GPS-enabled computer programs often don't know that, or care.