Free real-time traffic information

While talking with a good friend who had been stranded on the road during "Skidlocked D.C. 2011" -- a nightmare traffic jam that occurred throughout the Washington, D.C. metropolitan area during a snowstorm that began on the afternoon of 26 January -- he mentioned that his decision to return to work and hunker down for a while was based upon the free real-time traffic information available on Google Maps. As it turns out, the traffic information on Google Maps is at least as good as traffic info from any commercial service provider.

How does the Google Maps traffic overlay work so well? In a word, crowdsourcing. Huh? Here's how it works. When your GPS-enabled cell phone is turned on and location services enabled, the phone sends anonymous data to Google regarding the position of your phone. It is possible to determine the speed at which your cell phone is moving based upon the change in position of the phone as time passes. Now imagine that the position of your cell phone, as well as the positions of lots of other cell phones, happens to be co-located with a highway, and there you have it in a nutshell -- crowdsourced traffic information that can be used to display on a map both the volume of traffic and the speed at which it's moving. Very cool!

Related Resources:

• Google Maps Help
• Google Maps Help - Traffic
• Google Maps Help - Availability of real-time traffic
• Official Google Blog - The bright side of sitting in traffic: Crowdsourcing road congestion data

Tech Tips: Using the "Maps" app on the Apple iPhone: Tap the "map curl" (shown lower righthand corner of the screen) and select "Show Traffic." Using a Web browser on a computer: "To see if live traffic is available in your area, hover your mouse over the square widget on the top righthand corner of the map. A menu with available layers for your map will appear. Click on Traffic to turn on the layer and view real-time traffic conditions." (Credit: Google Maps Help)