Credit The New York Times
Q. How does the Google Maps app know there is a car stopped by the side of the highway or a jam up ahead?
A. Google pulls in traffic data from multiple sources for its Maps app, including information from police and local transportation departments. Many reports concerning real-time events â like cars stopped on the highway shoulder, debris on the road, construction, congestion and accidents â come from the users of its Waze service.
Waze, a company Google acquired in 2013, has mobile apps for Android and iOS devices. Waze members can use the app for navigation to a destination and to report traffic observations and incidents along the route. One screen within the Waze app provides a set of icons for users â typically passengers in the car â to update the appâs maps with new information, including stopped vehicles. These Waze reports are then incorporated into the Google Maps navigation, too.
Google has been collecting traffic and map data for more than a decade and gathering crowdsourced congestion reports since at least 2009, and the collection has given the company a long history of patterns and trends for its software to analyze. Google Maps users contribute to the traffic database, too, as speed and location information from devices using the app (inside the moving cars) is shared with the company.
The app uses a color code on routes to indicate current traffic conditions, including green for no delays, orange for a moderate amount of traffic and deepening shades of red as road congestion becomes worse and progress slows to a crawl. Last year, Google Maps added new traffic alerts that preview the conditions between you and your destination â and suggest alternate roads to get you there faster if an accident or other incident has occurred on your original route.