St. Tammany County Bridge Report Card
St. Tammany County scores 68 out of 100 on BridgeLookup's Bridge Condition Exposure Score, based on FHWA National Bridge Inventory records.
St. Tammany County, Louisiana
St. Tammany County has 361 bridges in the National Bridge Inventory, with 18 rated poor and 53 rated scour-critical. Its poor-condition share of 5.0% is at or below the 11.2% statewide average. Poor-condition bridges carry about 66,968 daily vehicle crossings.
Quote-Ready Local Facts
Copyable Facts for Reporters
BridgeLookup.com gives St. Tammany County a Bridge Condition Exposure Score of 68/100 (D). The county has 361 bridges in the National Bridge Inventory, including 18 in poor condition and 53 rated scour-critical. Poor-condition bridges carry about 66,968 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 | 5.0% | 10.0 |
| Poor-condition traffic exposure | 25 | 1.5% of measured traffic | 1.1 |
| Scour-critical bridge share | 20 | 14.7% | 20.0 |
| Average age vs national baseline | 10 | 49 years vs 48 nationally | 0.4 |
| Traffic-data completeness | 5 | 4,488,823 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 | 5.0% |
| State Poor-Condition Share | 11.2% |
| National Poor-Condition Share | 6.7% |
| County Scour-Critical Share | 14.7% |
| Average Bridge Age | 49 years |
| Poor-Condition Traffic Exposure | 66,968 vehicles/day |
Bridges to Watch
Top Bridges to Watch in St. Tammany County
| Bridge | Reason | Condition | Daily Traffic | Year Built |
|---|---|---|---|---|
| La0059 over Long Branch Bayou | Poor condition + traffic exposure | Poor | 4,612 | 1954 |
| La0036 over Abita River | Poor condition + traffic exposure | Poor | 1,844 | 1957 |
| Us0190 over Us190b/la21/bouge Falaya | Poor condition + traffic exposure | Poor | 28,900 | 1958 |
| Us0011 over No&ne Railroad | Poor condition + traffic exposure | Poor | 15,607 | 1937 |
| Dixie Ranch Rd. over I-12 | Poor condition + traffic exposure | Poor | 4,450 | 1972 |
| N. Wllie RD over Drainage Ditch | Poor condition + traffic exposure | Poor | 2,255 | 1990 |
| Us0090 over West Pearl River | Poor condition + traffic exposure | Poor | 1,215 | 1933 |
| Us0090 over West Middle River | Poor condition + traffic exposure | Poor | 1,215 | 1933 |
| Us0090 over Middle Middle Pearl Rive | Poor condition + traffic exposure | Poor | 1,215 | 1933 |
| Us0090 over E Middle Pearl River | Poor condition + traffic exposure | Poor | 1,215 | 1933 |
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.