Extent, connectivity, and condition of the transportation system

The United States has about 4 million miles of highways, 117,837 miles of railroad, about 1.6 million miles of oil and gas pipelines, and approximately 26,000 miles of navigable waterways. [A-1] If laid end to end, the nation's waterways would circle the Earth once, its railroads would circle the Earth nearly 5 times; its pipelines 64 times, and its roads 160 times.
It has 5,233 public use airports, 9,399 waterway facilities, 2,936 rail transit stations, and 505 Amtrak railway stations. [A-3, A-4, A-5]
Transportation capital stock, a measure of the amount of productive assets (buildings, structures, machinery, and equipment) in use at a particular time, reached $5.5 trillion in 2005, $2.5 trillion more than in 1995. Although highways and consumer motor vehicles constitute over $3.4 trillion of the total, all components have grown-with air growing fastest (more than doubling) between 1995 and 2005. [A-7]
In 2005, there were over 247 million highway motor vehicles (42 million more than in 1995), nearly 13 million recreational boats and vessels, 1.3 million railcars and locomotives, and 232,577 general aviation and commercial airplanes in the United States . [A-6]
Freight was hauled in over 9 million trucks (not including pickup trucks and other light trucks), rail cars, water vessels, and airplanes in 2005. [A-6]

The condition of interstates generally improved between 1995 and 2005, although some road categories (rural and urban collectors and urban minor arterials) showed a higher percentage of roads in poor or mediocre condition. [A-8]
The number of structurally deficient highway bridges declined between 1995 and 2006 while the total number of bridges increased; however, the percent of functionally deficient bridges increased between 1997 and 2006. [A-9]
Seventy-seven percent of airports identified in the National Plan of Integrated Airport Systems (NPIAS) as significant to national air transportation were in "good" condition in 2006; only 4 percent were in poor condition. [A-10]

The median age of passenger cars in 2006 was 9.2 years. [A-14]
The average age of full-size transit buses in 2005 was 7.6 years. [A-15]
The average age of all commercial aircraft in 2005 was 11.3 years. [A-18]
Between 1998 and 2005, the average freight loading capacity of oceangoing vessels calling at U.S. ports has increased by nearly 4,800 deadweight tons. [A-12]
Average loaded railcar weights have declined from the high point during the period of 1995 to 2005 (65.3 tons in 1995 to 61 tons in 2005). [A-13]

In 2006, 8.8 percent of U.S. households were without a vehicle. [A-19]
76 percent of people commuting drive themselves to work, while only 4.8 percent use mass transportation. [A-20]
The largest percent (15.1 percent in 2003 and 14.9 percent in 2006) of households depart to work between 7:00 am and 7:29 am. [A-21]

Bureau of Transportation Statistics