The Texas Transportation Institute at Texas A&M University (TTI) recently released the 2011 Congested Corridors Report, which documents the most congested freeway corridors throughout the country.  The data used in the report was collected in 2010 by Inrix from GPS-enabled vehicles traveling throughout the United States, including taxis, shuttles, trucks, and delivery vans.

Based on the criteria that these most congested corridors must be congested for 3 or more miles at least 4 hours each week, a total of 328 directional freeway corridors across the nation made their list.  In Hampton Roads, two corridors made TTI's most congested corridors list:  The Eastbound Hampton Roads Bridge-Tunnel and the Westbound Hampton Roads Bridge-Tunnel.
 
TTI not only looked at those corridors that have the most congestion but also those corridors that are the most unreliable, meaning that the congestion levels vary significantly from day to day.  This is based on a measure called the Buffer Index, which takes into account the extra amount of time a person must build into their schedule to nearly guarantee that they'll make it to their destination on time.  TTI also calculated congestion levels based on the Travel Time Index, which compares how long trips take during the most congested periods of the day versus uncongested conditions.

The Eastbound Hampton Roads Bridge-Tunnel ranked as one of the most unreliable congested facilities in the nation, with the fifth highest Buffer Index in the country according to the report.  The Travel Time Index for the Eastbound Hampton Roads Bridge-Tunnel was also high at 1.89, which means that the average trip taken at the Hampton Roads Bridge-Tunnel during rush hour takes 89% longer than the same trip takes during uncongested times of the day.  This Travel Time Index ranked 98th highest in the country.

In the Westbound direction, the Hampton Roads Bridge-Tunnel was more congested than the Eastbound direction, but was also more reliable.  The Westbound Hampton Roads Bridge-Tunnel had the 54th highest Buffer Index in the country in 2010, but was the 80th most congested corridor in the country with a Travel Time Index of 1.96.

More information on the 2011 Congested Corridors Report is available on TTI's website at http://mobility.tamu.edu/corridors.