The U.S. has 614,387 bridges, almost four in 10 of which are 50 years or older. 56,007 — 9.1% — of the nation’s bridges were structurally deficient in 2016, and on average there were 188 million trips across structurally deficient bridges each day. While the number of bridges that are in such poor condition as to be considered structurally deficient is decreasing, the average age of America’s bridges keeps going up and many of the nation’s bridges are approaching the end of their design life. The most recent estimate puts the nation’s backlog of bridge rehabilitation needs at $123 billion.
Over the past decade, there has been increased awareness of the significance of bridges to our nation’s economy and the safety of the traveling public. At all levels of government, a concerted effort has been made to reduce the number of structurally deficient bridges in the U.S.—bridges that require significant maintenance, rehabilitation, or replacement. Structurally deficient bridges are not unsafe, but could become so and need to be closed without substantial improvements.
In recent years, investment at all levels of government has prioritized fixing bridges. The federal government estimates that $17.5 billion was spent on bridge capital projects in 2012, with $6 billion from the federal government and $11.5 billion from state and local sources. This is a substantial increase from the $11.5 billion that was spent on bridges in 2006. Investments in bridges were bolstered in 2009 and 2010 with the influx of additional funding from the American Recovery and Reinvestment Act and peaked in 2010 with $18 billion spent. Despite the recent increases in spending, investments in the country’s bridges are insufficient. The most recent federal estimate puts the backlog of rehabilitation projects for the nation’s bridges at $123 billion. See the Roads chapter for more information on public spending on highways, including bridges.
New technologies and materials are helping engineers build bridges better and faster while also improving maintenance for longer bridge life. Sensors are being embedded into both new and existing bridges to provide continuous feedback on structural conditions. These data help engineers identify and address problems earlier and improve public safety. New materials such as ultra-high performance concrete, high performance steel, and composites are being used to add durability, higher strengths, resilience, and longer life to bridges. Prefabricated bridge elements—structural components that are built off-site—are being used to reduce the amount of time traffic needs to be disrupted while a bridge is repaired or constructed.
Raising the Grades
Solutions that Work Now
Increase funding from all levels of government to continue reducing the number of structurally deficient bridges, decrease the maintenance backlog, and address the large number of bridges that have passed or are approaching the end of their design life.
Bridge owners should consider the costs across a bridge’s entire lifecycle to make smart design decisions and prioritize maintenance and rehabilitation.
Fix the federal Highway Trust Fund by raising the federal motor fuels tax. To ensure long-term, sustainable funding for the federal surface transportation program, the current user fee of 18.4 cents per gallon on gasoline and 24.4 cents per gallon on diesel should be raised and tied to inflation to restore its purchasing power, fill the funding deficit, and ensure reliable funding for the future.
States should ensure their funding mechanisms (motor fuels taxes or other) are sufficient to fund needed investment in bridges.
States and the federal government should consider long-term funding solutions for transportation infrastructure and potential alternatives to the motor fuel taxes, including further study and piloting of mileage-based user fees.