"The Unsafe Bridges of Iowa Counties" wouldn't be an appealing feature film, but it could be an appropriate subject for a documentary. The Transportation for America coalition released a report today on the state of bridges in the U.S., and the results are not pretty for Iowa. Nationwide, "69,223 bridges - 11.5 percent of total highway bridges in the U.S. - are classified as 'structurally deficient,' requiring significant maintenance, rehabilitation or replacement." Table 1 and Appendix A of the full report (pdf) rank the states by percentage of structurally deficient bridges. Iowa's percentage is nearly twice the national average: 21.7 percent of our state's bridges are deficient. Only Pennsylvania and Oklahoma scored worse on this metric. Iowa is among just five states in which more than 20 percent of bridges are structurally deficient.
Appendix B shows the two busiest structurally deficient bridges in each state. In Iowa, those are an I-80/I-35 bridge over a drainage ditch in Polk County (average daily traffic 82,100 vehicles) and an I-29 bridge over the Floyd River in Woodbury County (average daily traffic 42,100 vehicles).
Appendix C shows the 100 worst counties nationwide in terms of percentage of deficient bridges. Iowa has 17 counties on this list, more than any other state.
Iowa has an unusually large number of towns and more road miles per capita than any other state, to my knowledge. Historically, our state's political leaders have been reluctant to borrow to pay for infrastructure needs, which explains Iowa's relatively low debt load and the furious Republican reaction to the last administration's I-JOBS infrastructure bonding initiative. Some states routinely borrow to cover infrastructure projects, including our neighbor to the north. I wonder if Minnesota's much larger state borrowing than Iowa over the years is one reason the state does relatively well in Transportation for America's report (8.8 percent of bridges in the state are structurally deficient).
In the past, federal highway money has gone predominantly toward building new roads. The Transportation for America report advocates more federal assistance to states for fixing roads and bridges:
Allowing roads and bridges to slip into disrepair ultimately costs state and local governments billions more than the cost of regular, timely repair. Over a 25-year period, deferring maintenance of bridges and highways can cost three times as much as preventative repairs. The backlog also increases safety risks, hinders economic prosperity and significantly burdens taxpayers.
Preservation efforts can also extend the expected service life of a road for an additional 18 years, preventing the need for major reconstruction or replacement.4 In addition to the safety imperative, investing in the construction, expansion and repair of our nation's transportation infrastructure creates jobs today while laying the foundation for long- term economic prosperity. Repair work on roads and bridges generates 16 percent more jobs than construction of new bridges and roads.5
A recent report on the use of federal stimulus funds for transportation showed that maintenance projects created more jobs per dollar spent than new road construction.
Transportation for America's full report is here. After the jump I've posted the 17 Iowa counties that made Appendix C (worst 100 counties nationwide) and the percentage of deficient bridges in each. I also posted an excerpt from the report explaining the criteria for naming a bridge "structurally deficient."
This page at Transportation for America's website includes a map and chart with information about all 99 Iowa counties: number of bridges, number of structurally deficient bridges, percent of bridges that are structurally deficient, bridge average annual daily traffic and average daily traffic on structurally deficient bridges. After the jump I've posted an excerpt from that page showing Iowa's five best and five worst counties in this area.
Transportation for America, The Fix We're In For: The State of Our Bridges.
From Appendix C: the 100 worst U.S. counties
10. Adams 94 of the 202 bridges (46.5 percent) deficient
14. Winnebago 49 of the 111 bridges (44.1 percent) deficient
17. Davis 91 of the 210 bridges (43.3 percent) deficient
29. Lucas 79 of the 203 bridges (38.9 percent) deficient
30. Plymouth 208 of the 535 bridges (38.9 percent) deficient
32. Keokuk 80 of the 209 bridges (38.3 percent) deficient
35. Taylor 96 of the 255 bridges (37.6 percent) deficient
48. Boone 48 of the 136 bridges (35.3 percent) deficient
49. Guthrie 97 of the 276 bridges (35.1 percent) deficient
51. Monroe 52 of the 149 bridges (34.9 percent) deficient
55. Van Buren 58 of the 167 bridges (34.7 percent) deficient
64. Warren 93 of the 270 bridges (34.4 percent) deficient
75. Adair 107 of the 319 bridges (33.5 percent) deficient
76. Jefferson 55 of the 164 bridges (33.5 percent) deficient
90. Tama 118 of the 362 bridges (32.6 percent) deficient
96. Ringgold 82 of the 254 bridges (32.3 percent) deficient
97. Hancock 50 of the 155 bridges (32.3 percent) deficient
From a sidebar on page 4 of the report:
What Qualifies a Bridge as "Structurally Deficient?"
Highway bridges have three components: 1) the superstructure, which supports the deck; 2) the substructure, which uses the ground to sup- port the superstructure; and 3) the deck, which is the top surface of the bridge that cars, trucks and people cross. During inspection, each of these bridge features is given a rating between 0 and 9, with 9 signifying the best condition. These individual ratings, as well as other factors, are combined to establish a bridge's overall "suffi- ciency rating," scored 1 to 100. Federal guidelines classify bridges as "structurally deficient" if one
of the three key components is rated at 4 or less (poor or worse), meaning engineers have identified a major defect in its support structure or its deck. Deficient bridges require significant maintenance, rehabilitation or replacement. A state may have to restrict heavy vehicle traffic, conduct immediate re- pairs to allow unrestricted use or close the bridge to traffic until repairs can be completed. Federal law requires states to inspect all bridges 20 feet or longer at least every two years. Bridges in "very good" condition may go four years between in- spections, while those rated "structurally deficient" must be inspected every year.
Sources: Federal Highway Administration. "Non-Reg- ulatory Supplement." U.S. Department of Transporta- tion. http://www.fhwa.dot.gov/legsre... fapg/0650dsup.htm#N_2_
Federal Highway Administration. "Conditions & Perfor- mance." U.S. Department of Transportation, 2006.
From the Iowa page of Transportation for America's report "The Fix We're In For: The State of Our Bridges":
Best Counties Deficient
Dubuque County 6.7%
Linn County 5.6%
Osceola County 5.3%
Jackson County 4.2%
Clinton County 3.7%
Worst Counties Deficient
Adams County 46.5%
Winnebago County 44.1%
Davis County 43.3%
Lucas County 38.9%
Plymouth County 38.9%