Forty-five of the 405 bridges in the Greater Des Moines metropolitan area are deemed “structurally deficient,” a recent analysis finds.

The Des Moines Area Metropolitan Planning Organization (MPO) analyzed data from the National Bridge Inventory to develop a status report of bridge conditions in the Greater Des Moines metropolitan area. Findings of the MPO’s Quality of Our Bridges Report include:

• 45 bridges (11 percent of 405 total bridges) are classified as “structurally deficient,” a federal classification given to bridges that need significant maintenance, rehabilitation or replacement. Though given this classification, the bridges can still safely support vehicle traffic, are inspected biannually by the Iowa Department of Transportation, and would be closed if found to be unsafe.
• 60 bridges (15 percent of 405 total bridges) are classified as “functionally obsolete,” a federal classification for bridges that no longer meet current design criteria, due to such factors as traffic volumes or lane widths.
• 59 percent of the deck area of all 405 metro-area bridges combined is classified in good condition, 33 percent in fair condition and 8 percent in poor condition. This is better than the Federal Highway Administration’s proposed target of no more than 10 percent of deck area in poor condition.

• 81 bridges (20 percent of 405 total bridges) are eligible for federal funding through the Highway Bridge Replacement and Rehabilitation Program due to their being classified as either structurally deficient or functionally obsolete with a sufficiency rating below 80 on a 100-point scale.
• 28 percent of bridges in Environmental Justice Areas are classified as being structurally deficient or functionally obsolete, compared to 26 percent of the bridges outside these areas. These areas include higher than average concentrations of persons 65 years old and older, persons with disabilities, persons with limited-English proficiency, non-white population, persons in poverty, carless households and single heads of households with children.

The Quality of Our Bridges Report finds that the region is on track to maintaining current bridge conditions, a goal outlined in the long-range transportation plan Mobilizing Tomorrow. The target is to maintain bridges such that no more than 25 percent are classified as structurally deficient or functionally obsolete; currently, the region is within one percentage point of meeting that goal, at 26 percent.

For more information, please call or email MPO staff at 515-334-0075 or info@dmampo.org.