The most recent data show continuing increases in highway congestion for many urban areas in the United States. Congestion in the United States, as measured by the Travel Time Index (TTI), increased for the largest urban areas from 1.36 in 2004 to 1.38 in 2005 (Table 2-3-4: Travel Time Index by Metro Area). From 1982 to 2005, congestion for all urban areas increased 17 percent, while congestion for very large urban areas increased 21 percent. Average hours of delay also increased. From 2004 to 2005, very large urban areas experienced an average of three additional annual hours of delay per traveler, representing a 5.9 percent annual increase (Table 2-3-5: Average Hours of Annual Delay per Traveler).
Only moderate changes occurred in vehicle miles-traveled and passenger miles-traveled from 2005 to 2006, with two exceptions, light truck passenger-miles increased 4.6 percent and transit car passenger-miles increased 5.0 percent (Table 2-3-1: U.S. Vehicle-Miles, Table 2-3-2: U.S. Passenger-Miles). Railroads were the only mode exhibiting a large change in freight ton-miles, increasing 6.9 percent from 2005 to 2006 (Table 2-3-3: Index of Ton-Miles of Freight).
In 2007, average wait times for passengers increased at both the U.S.-Canada border (from 8.3 minutes to 12.6 minutes) and the U.S.-Mexico border (from 21.6 minutes to 27.8 minutes) The average wait time for commercial vehicles at the U.S.-Canada border increased from 7.5 minutes to 8.3 minutes, but the average wait time at the U.S.-Mexico border decreased from 12.6 minutes to 11.9 minutes (Table 2-3-7: Average Daytime Wait Times for Commercial Vehicles at Selected U.S. Surface Border Gateways).
The St. Lawrence Seaway experienced an increase in total downtime hours, from 62.4 hours in 2006 to 73.7 hours in 2007, as a result of a large increase in weather-related downtime, from 19.1 hours to 39.7 hours (Table 2-3-8: St. Lawrence Seaway U.S. Locks Downtime by Cause).