St. Louis County Bridge Report Card
St. Louis County scores 83 out of 100 on BridgeLookup's Bridge Condition Exposure Score, based on FHWA National Bridge Inventory records.
St. Louis County, Missouri
St. Louis County has 1,145 bridges in the National Bridge Inventory, with 67 rated poor and 5 rated scour-critical. Its poor-condition share of 5.9% is at or below the 8.8% statewide average. Poor-condition bridges carry about 1,431,892 daily vehicle crossings.
Quote-Ready Local Facts
Copyable Facts for Reporters
BridgeLookup.com gives St. Louis County a Bridge Condition Exposure Score of 83/100 (B). The county has 1,145 bridges in the National Bridge Inventory, including 67 in poor condition and 5 rated scour-critical. Poor-condition bridges carry about 1,431,892 daily vehicle crossings. Poor condition does not mean unsafe; bridges judged unsafe are closed or restricted by transportation agencies.
How the Score Breaks Down
| Factor | Weight | County Value | Penalty |
|---|---|---|---|
| Poor-condition bridge share | 40 | 5.9% | 11.7 |
| Poor-condition traffic exposure | 25 | 5.6% of measured traffic | 4.2 |
| Scour-critical bridge share | 20 | 0.4% | 0.9 |
| Average age vs national baseline | 10 | 39 years vs 48 nationally | 0.0 |
| Traffic-data completeness | 5 | 25,704,408 measured daily crossings | 0.0 |
Score = 100 minus weighted penalties. The score is a comparative research signal, not an official safety rating. Read the full methodology.
County Comparisons
| County Poor-Condition Share | 5.9% |
| State Poor-Condition Share | 8.8% |
| National Poor-Condition Share | 6.7% |
| County Scour-Critical Share | 0.4% |
| Average Bridge Age | 39 years |
| Poor-Condition Traffic Exposure | 1,431,892 vehicles/day |
Bridges to Watch
Top Bridges to Watch in St. Louis County
| Bridge | Reason | Condition | Daily Traffic | Year Built |
|---|---|---|---|---|
| Is 44 W over Meramec Rvr South Outer | Poor condition + traffic exposure | Poor | 37,539 | 1968 |
| Is 270 E over Cst Conway RD | Poor condition + traffic exposure | Poor | 182,944 | 1964 |
| Is 270 E over Cst West Port Plaza DR | Poor condition + traffic exposure | Poor | 137,112 | 1965 |
| Is 270 E over Maline CR | Poor condition + traffic exposure | Poor | 111,723 | 1931 |
| Is 170 E over Rvr Des Peres | Poor condition + traffic exposure | Poor | 97,246 | 1968 |
| Is 64 W over Co North Forty DR To Sor | Poor condition + traffic exposure | Poor | 71,687 | 1985 |
| Is 64 E over Co North Forty DR To Sor | Poor condition + traffic exposure | Poor | 64,631 | 1985 |
| Is 64 E over Cst Vandeventer AVE Cst | Poor condition + traffic exposure | Poor | 59,295 | 1956 |
| Kingshighway over Metrolink | Poor condition + traffic exposure | Poor | 45,900 | 1937 |
| Is 55 N over Mo Pac Rr | Poor condition + traffic exposure | Poor | 44,800 | 1963 |
Important safety note
Poor condition does not mean a bridge is unsafe. It means at least one major component has significant deterioration and the bridge is a priority for maintenance, repair, or replacement. Bridges judged unsafe are closed or restricted by transportation agencies.