Grundy County Bridge Report Card
Grundy County scores 49 out of 100 on BridgeLookup's Bridge Condition Exposure Score, based on FHWA National Bridge Inventory records.
Grundy County, Illinois
Grundy County has 268 bridges in the National Bridge Inventory, with 76 rated poor and 2 rated scour-critical. Its poor-condition share of 28.4% is above the 9.5% statewide average. Poor-condition bridges carry about 86,325 daily vehicle crossings.
Quote-Ready Local Facts
Copyable Facts for Reporters
BridgeLookup.com gives Grundy County a Bridge Condition Exposure Score of 49/100 (F). The county has 268 bridges in the National Bridge Inventory, including 76 in poor condition and 2 rated scour-critical. Poor-condition bridges carry about 86,325 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 | 28.4% | 40.0 |
| Poor-condition traffic exposure | 25 | 13.2% of measured traffic | 9.9 |
| Scour-critical bridge share | 20 | 0.7% | 1.5 |
| Average age vs national baseline | 10 | 41 years vs 48 nationally | 0.0 |
| Traffic-data completeness | 5 | 652,585 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 | 28.4% |
| State Poor-Condition Share | 9.5% |
| National Poor-Condition Share | 6.7% |
| County Scour-Critical Share | 0.7% |
| Average Bridge Age | 41 years |
| Poor-Condition Traffic Exposure | 86,325 vehicles/day |
Bridges to Watch
Top Bridges to Watch in Grundy County
| Bridge | Reason | Condition | Daily Traffic | Year Built |
|---|---|---|---|---|
| Tr-91b Valerio RD over Claypool DR Ditch | Poor condition + traffic exposure | Poor | 100 | 1916 |
| Tr-167 Scully RD over Trib E Fk Mazon Riv | Poor condition + traffic exposure | Poor | 50 | 1910 |
| Ill 47 over Armstrong & B & O Rr | Poor condition + traffic exposure | Poor | 21,000 | 1978 |
| Ill 47 over Buchanan ST | Poor condition + traffic exposure | Poor | 21,000 | 1978 |
| US 6 over Aux Sable CR | Poor condition + traffic exposure | Poor | 7,050 | 1969 |
| US 6 over Csx Railroad | Poor condition + traffic exposure | Poor | 7,050 | 1974 |
| Broadway ST N/ms60 over Claypool Drain Ditch | Poor condition + traffic exposure | Poor | 1,850 | 1982 |
| Ashton RD / Tr 106 over Fai 80 | Poor condition + traffic exposure | Poor | 1,650 | 1958 |
| Tr-204 Dresden RD over Com.ed.flumes | Poor condition + traffic exposure | Poor | 1,400 | 1975 |
| Ch-41 over Granary Creek | Poor condition + traffic exposure | Poor | 1,400 | 1977 |
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.