In 1997, over 230 million motor vehicles, ships, airplanes, and railroad cars were used on 6.4 million km (4 million miles) of highways, railroads, airports, and waterways. The transportation infrastructure also includes over 800,000 km (approximately 500,000 miles) of oil and gas transmission pipelines, and 18,000 public and private airports. The annual direct cost of corrosion in the infrastructure category is estimated at $22.6 billion, which is 16.4% of the total cost of the sector categories examined in the study. The infrastructure category is divided into six industry sectors: highway bridges, gas and liquid transmission pipelines, waterways and ports, hazardous materials storage, airports, and railroads.

Highway Bridges

As of 1998, there were 583,000 bridges in the United States. At that time, approximately 15% of the bridges were structurally deficient, primarily due to corrosion of steel and steel reinforcement. The annual direct cost of corrosion for highway bridges is estimated to be $8.3 billion, consisting of $3.8 billion to replace structurally deficient bridges over the next ten years, $2.0 billion for maintenance and cost of capital for concrete bridge decks, $2.0 billion for maintenance and cost of capital for concrete substructures (not including decks), and $0.5 billion for maintenance painting of steel bridges. Life-cycle analysis estimates indirect costs to the user due to traffic delays and lost productivity at more than ten times the direct cost of corrosion maintenance, repair, and rehabilitation.

Gas and Liquid Transmission Lines

There are over 528,000 km (328,000 miles) of natural gas transmission and gathering pipelines, 119,000 km (74,000 miles) of crude oil transmission and gathering pipelines, and 132,000 km (82,000 miles) of hazardous liquid transmission pipelines. At an estimated replacement cost of $643,800 per km ($1,117,000 per mile), the asset replacement value of the transmission pipeline system in the United States is $541 billion; therefore a significant investment is at risk with corrosion being the primary factor in controlling the life of the asset.

Significant maintenance costs for pipeline operation is associated with corrosion control and integrity management. The driving force for maintenance expenditures is to preserve the asset of the pipeline and to ensure safe operation without failures that may jeopardize public safety, result in product loss, or cause property and environmental damage. With a range of corrosion operation and maintenance costs of $3,100 to $6,200 per km ($5,000 to $10,000 per mile), the total corrosion operation and maintenance cost ranges from $2.42 billion to $4.84 billion. The average annual corrosion-related cost is estimated at $7.0 billion, which can be divided into the cost of capital (38%), operation and maintenance (52%), and failures (10%).

Waterways & Ports

In the United States, 40,000 km (25,000 miles) of commercial navigable waterways serve 41 states, including all states east of the Mississippi. Hundreds of locks facilitate travel along these waterways. In January 1999, 135 of the 276 locks had exceeded their 50-year design life. U.S. ports play an important role in connecting waterways, railroads, and highways. The Nation's ports include 1,914 deep water (seacoast and Great Lakes) and 1,812 along inland waterways. Corrosion is typically found on piers and docks, bulkheads and retaining walls, mooring structures, and navigational aids. There is no formal tracking of corrosion costs in these structures. Based on cost numbers obtained from the Army Corps of Engineers and Coast Guard, an annual corrosion cost of $0.3 billion could be estimated. It should be noted that this is a low estimate since the corrosion costs of harbor and other marine structures are not included.

Hazardous Materials Storage

The United States has approximately 8.5 million regulated and non-regulated aboveground storage tanks (ASTs) and underground storage tanks (USTs) for hazardous materials (HAZMAT). While these tanks represent a large investment and good maintenance practices would be in the best interest of the owners, Federal and State environmental regulators are concerned with the environmental impact of spills from leaking tanks. The U.S. Environmental Protection Agency set a December 1998 deadline for UST owners to comply with requirements for corrosion control on all tanks, as well as overfill and spill protection. In case of non-compliance, tank owners face considerable costs related to clean up and penalties. The total annual direct cost of corrosion for HAZMAT storage is $7.0 billion, divided between $4.5 billion for ASTs and $2.5 billion for USTs.

Airports

The United States has the world's most extensive airport system, which is essential to national transportation and the U.S. economy. According to the 1999 Bureau of Transportation Statistics, there were 5,324 public-use airports and 13,774 private-use airports in the United States. A typical airport infrastructure is complex, and components that might be subject to corrosion include the natural gas distribution system, jet fuel system storage and distribution system, deicing storage and distribution system, vehicle fueling systems, natural gas feeders, dry fire lines, parking garages, and runway lighting. Generally, each of these systems is owned or operated by different organizations or companies; therefore, the impact of corrosion on an airport as a whole is not known or documented.

Railroads

In 1997, there were nine Class I freight railroads accounting for 71% of the industry's 274,399 km (170,508 miles) operated. There were 35 regional railroads operating 34,546 km (21,466 miles) and 513 local railroads operating over 45,300 km (28,149 mi) of railroad. The elements that are subject to corrosion include metal members, such as rail and steel spikes; however, corrosion damage to railroad components are either limited or go unreported. Hence, an accurate estimate of the corrosion cost could not be determined.