Our exclusive annual research into bridge conditions in the United States.

Over regulated, underfunded and disheartening.”

That’s how Brian Olson, bridge replacement engineer with the South Dakota Department of Transportation, describes the past 12 months for his department in terms of work and funding.

There is no avoiding the obvious – our economy and spending on transportation infrastructure are both weak and showing precious little signs of a sudden, strong and prolonged revival. But despite the doom and gloom that’s been cast on U.S. infrastructure, the state of the nation’s bridges could be said to be a little bit encouraging.

A Five-Year Look at America’s Bridge Inventory

Better Roads’ annual Bridge Inventory reveals that the total number of structurally deficient (SD) and functionally obsolete (FO) bridges (combined) has dropped from 23.3 percent last year to 22.7 percent this year. That means 136,816 of the total 602,091 bridges surveyed are SD/FO (combined) this year. Last year, 600,513 bridges were surveyed and 139,620 of them were SD/FO (combined).

Of the nation’s 292,085 total interstate and state bridges, 59,250, or 20.3 percent, are SD/FO (combined). In 2010, Better Roads reported 61,149, or 21 percent, of the 291,034 total interstate and state bridges were SD/FO (combined).

Highest Percentage of SD/FO State/Interstate bridges

There are 310,006 total city/county/township bridges in the United States, and 77,566 – or 25 percent – are SD/FO (combined). In 2010, of the 309,479 reported total city/county/township bridges, 78,471 (25 percent) were considered SD/FO (combined).

There has been steady decline in the number of overall SD/FO combined bridges in the United States, as well as the number of SD/FO combined bridges at the interstate and state level and at the city/county/township level since Better Roads first began archiving its Bridge Inventory in 1985. In fact, there has been a 19.8-percent decline in overall total SD/FO combined bridges. In 1985, 42.5 percent of the total 586,241 bridges surveyed in the nation were SD/FO combined. (The survey was started in 1979, but the data were not archived until 1985, the year the survey received responses from all 50 states and the District of Columbia.) Ten years later, 591,205 total bridges were surveyed and 187,504, or 31.7 percent, were reported as SD/FO (combined). In 2005, the Bridge Inventory’s total number of surveyed bridges grew to 595,625, but only 25 percent, or 149,126 were SD/FO (combined). From 2006 to 2011, there has been a 1.8-percent drop – from 24.5 percent to the current 22.7 percent – in the number of SD/FO combined bridges.

The top states with the most city/county/township SD/FO bridges

Looking at the numbers state-by-state, the majority of jurisdictions have slightly, decreased the number of SD/FO (combined) bridges. It may be baby steps, but it’s a move in the right direction.

But one exception with a significant rise in percentage was Washington, D.C., which has jumped from 41 percent in 2007 to a current rate of 61 percent.