August 16, 2010 7:00 am
Q.
I have the traffic conditions option in Google Maps turned on my phone. I understand that the red, yellow and green lines give a general idea of how bad traffic is on a road, but do they have any specific meaning, like red equals a 40-minute wait at a toll bridge?
A.
According to the Google Maps site, the colored lines representing traffic conditions on major highways refer to the speed at which one can travel on that road.
The dreaded red lines mean highway traffic is moving at less than 25 miles per hour and could indicate an accident or congestion on that route. Yellow lines on the map mean traffic is moving faster, from 25 to 50 miles per hour, while green lines mean traffic is zipping along at 50 miles per hour or more. If you see gray lines, that means there’s no traffic information available at the time and a red-black line refers to extremely slow or stopped traffic.
If you’re looking at traffic on city streets, where the speed limits are much lower than on the highways, the colors take on more of a relative meaning. Red (or red-black) lines mean a lot of slow going and general congestion. Yellow is a little better but still not the best for city travel, and green means traffic conditions are good.
Last year, Google asked for volunteers to help collect traffic data through the version of Google Maps for mobile phones. With GPS location services enabled and your permission to do so, your phone can send anonymous bits of speed and location information back to Google’s servers to help calculate real-time traffic conditions better.
