Snohomish County Bridge Report Card
Snohomish County scores 77 out of 100 on BridgeLookup's Bridge Condition Exposure Score, based on FHWA National Bridge Inventory records.
Snohomish County, Washington
Snohomish County has 500 bridges in the National Bridge Inventory, with 20 rated poor and 33 rated scour-critical. Its poor-condition share of 4.0% is at or below the 5.6% statewide average. Poor-condition bridges carry about 176,353 daily vehicle crossings.
Quote-Ready Local Facts
Copyable Facts for Reporters
BridgeLookup.com gives Snohomish County a Bridge Condition Exposure Score of 77/100 (C). The county has 500 bridges in the National Bridge Inventory, including 20 in poor condition and 33 rated scour-critical. Poor-condition bridges carry about 176,353 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 | 4.0% | 8.0 |
| Poor-condition traffic exposure | 25 | 2.3% of measured traffic | 1.7 |
| Scour-critical bridge share | 20 | 6.6% | 13.2 |
| Average age vs national baseline | 10 | 45 years vs 48 nationally | 0.0 |
| Traffic-data completeness | 5 | 7,692,983 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 | 4.0% |
| State Poor-Condition Share | 5.6% |
| National Poor-Condition Share | 6.7% |
| County Scour-Critical Share | 6.6% |
| Average Bridge Age | 45 years |
| Poor-Condition Traffic Exposure | 176,353 vehicles/day |
Bridges to Watch
Top Bridges to Watch in Snohomish County
| Bridge | Reason | Condition | Daily Traffic | Year Built |
|---|---|---|---|---|
| SR 529 over Steamboat Slough | Poor condition + traffic exposure | Poor | 16,592 | 1927 |
| SR 529 over Snohomish River | Poor condition + traffic exposure | Poor | 16,286 | 1954 |
| SR 203 over Drainage Overflow | Poor condition + traffic exposure | Poor | 12,132 | 1954 |
| Locust Way over Swamp Creek | Poor condition + traffic exposure | Poor | 8,654 | 1960 |
| US 2 over S Fk Skykomish River | Poor condition + traffic exposure | Poor | 6,408 | 1933 |
| Alderwood Mall Blv over SR 524/196th ST SW | Poor condition + traffic exposure | Poor | 19,198 | 1999 |
| SR 529 over Union Sl | Poor condition + traffic exposure | Poor | 16,439 | 1927 |
| SR 529 over Union Sl | Poor condition + traffic exposure | Poor | 16,439 | 1954 |
| SR 529 over Snohomish River | Poor condition + traffic exposure | Poor | 16,286 | 1927 |
| SR 203 over Skykomish River | Poor condition + traffic exposure | Poor | 15,153 | 1957 |
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.