Canyon County Bridge Report Card
Canyon County scores 90 out of 100 on BridgeLookup's Bridge Condition Exposure Score, based on FHWA National Bridge Inventory records.
Canyon County, Idaho
Canyon County has 291 bridges in the National Bridge Inventory, with 6 rated poor and 7 rated scour-critical. Its poor-condition share of 2.1% is at or below the 5.4% statewide average. Poor-condition bridges carry about 30,310 daily vehicle crossings.
Quote-Ready Local Facts
Copyable Facts for Reporters
BridgeLookup.com gives Canyon County a Bridge Condition Exposure Score of 90/100 (A). The county has 291 bridges in the National Bridge Inventory, including 6 in poor condition and 7 rated scour-critical. Poor-condition bridges carry about 30,310 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 | 2.1% | 4.1 |
| Poor-condition traffic exposure | 25 | 1.3% of measured traffic | 1.0 |
| Scour-critical bridge share | 20 | 2.4% | 4.8 |
| Average age vs national baseline | 10 | 41 years vs 48 nationally | 0.0 |
| Traffic-data completeness | 5 | 2,262,258 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 | 2.1% |
| State Poor-Condition Share | 5.4% |
| National Poor-Condition Share | 6.7% |
| County Scour-Critical Share | 2.4% |
| Average Bridge Age | 41 years |
| Poor-Condition Traffic Exposure | 30,310 vehicles/day |
Bridges to Watch
Top Bridges to Watch in Canyon County
| Bridge | Reason | Condition | Daily Traffic | Year Built |
|---|---|---|---|---|
| Stc 3851;hexon RD over Boise River | Poor condition + traffic exposure | Poor | 560 | 1954 |
| Nhs 7773;10th AVE over City St;uprr;caldwell Op | Poor condition + traffic exposure | Poor | 19,500 | 1956 |
| Blaine ST over Old Indian Creek Channel | Poor condition + traffic exposure | Poor | 5,400 | 1966 |
| Stc 7787;plymouth over Boise River & Canal | Poor condition + traffic exposure | Poor | 2,100 | 1922 |
| Sma 7733;kimball A over Indian Creek | Poor condition + traffic exposure | Poor | 2,000 | 1933 |
| Stc 8317;duff Lane over Willow Creek | Poor condition + traffic exposure | Poor | 750 | 1983 |
| I 84b;centennial W over Uprr;indian Cr;caldwell | Scour-critical foundation rating | Fair | 26,000 | 1983 |
| 7th AVE N. over Indian Creek | Scour-critical foundation rating | Good | 8,000 | 1978 |
| US 20 26;fap 21spr over Snake River;nyssa Bridge | Scour-critical foundation rating | Fair | 5,300 | 1957 |
| US 95 over Boise River | Scour-critical foundation rating | Fair | 3,900 | 1961 |
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.