The 2011 Congested Corridors Report is the first nationwide effort to identify reliability problems at specific stretches of highway responsible for significant traffic congestion at different times and different days. Analyses are performed along 328 specific (directional) freeway corridors in the United States. These corridors include many of the worst places for congestion in the United States, and the detailed data allow for more extensive analysis and a better picture of the locations, times and effects of stop-and-go traffic.