"Waze is an application, primarily for Google Android phones, that gathers data and provides it to the driver. Waze is able to use your GPS and your movement to determine if there is a traffic jam, an open route, or a previously unknown alleyway. It relies on multiple data points from multiple phones to provide a full picture of the area. As more and more users drive a specific area, it picks up on the streets, tendencies, and more to build a driver-generated map. This map not only includes streets, but builds in models for bottlenecks and major delays (red), fast routes, accidents, etc. Users can also actively report things like a speeding camera or a construction zone in order to build a more accurate Waze map." - Alan Cheslow from Bookmarklet