The 10 Least Reliable Roads in the United States

Just in time for the Thanksgiving rush home, the Texas Transportation Institute has released a national ranking of America's most-congested highway corridors. The institute, which is known for its annual mobility report of traffic in metro regions, analyzed 328 stretches of freeway at least three miles long during various periods of time. The results reach across several categories of congestion, including per-mile delay, morning and evening commute, and midday and weekend peaks.

The report's chief set of rankings is organized by what the institute calls a "buffer index." That metric is used to examine how reliable a certain corridor is during peak weekday periods. A buffer index of 50 percent, for instance, means drivers on this route should allot 50 percent more time to reach their destination without being late. (To be a bit more precise: the index asks how much time you need to make sure that in 95 percent of your trips you won't be late.) So a trip that should take 30 minutes becomes a 45-minute ride on a corridor with a 50 percent buffer index.