How are the different congestion levels shown in the Traffic Congestion layer translated into speeds?
Traffic conditions are delineated by color bands along the roadways. Each color denotes a different level of congestion. The following table shows the defined congestion levels displayed in the Traffic Congestion legend. Note that speed ranges are calculated as a percentage of the speed limit for each roadway segment. The “No Data” congestion level is used to indicate roadways for which there is no information currently available that would allow a congestion level to be determined.