Sangamon County Bridge Report Card
Sangamon County scores 84 out of 100 on BridgeLookup's Bridge Condition Exposure Score, based on FHWA National Bridge Inventory records.
Sangamon County, Illinois
Sangamon County has 464 bridges in the National Bridge Inventory, with 28 rated poor and 0 rated scour-critical. Its poor-condition share of 6.0% is at or below the 9.5% statewide average. Poor-condition bridges carry about 91,635 daily vehicle crossings.
Quote-Ready Local Facts
Copyable Facts for Reporters
BridgeLookup.com gives Sangamon County a Bridge Condition Exposure Score of 84/100 (B). The county has 464 bridges in the National Bridge Inventory, including 28 in poor condition and 0 rated scour-critical. Poor-condition bridges carry about 91,635 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 | 6.0% | 12.1 |
| Poor-condition traffic exposure | 25 | 4.8% of measured traffic | 3.6 |
| Scour-critical bridge share | 20 | 0.0% | 0.0 |
| Average age vs national baseline | 10 | 45 years vs 48 nationally | 0.0 |
| Traffic-data completeness | 5 | 1,922,650 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 | 6.0% |
| State Poor-Condition Share | 9.5% |
| National Poor-Condition Share | 6.7% |
| County Scour-Critical Share | 0.0% |
| Average Bridge Age | 45 years |
| Poor-Condition Traffic Exposure | 91,635 vehicles/day |
Bridges to Watch
Top Bridges to Watch in Sangamon County
| Bridge | Reason | Condition | Daily Traffic | Year Built |
|---|---|---|---|---|
| I-55 (nb) over Il 104 / I & M Rr | Poor condition + traffic exposure | Poor | 15,550 | 1972 |
| I-55 (sb) over Il 104 / I & M Rr | Poor condition + traffic exposure | Poor | 15,550 | 1972 |
| I-55 (nb) over Bl 55 & Up Rr | Poor condition + traffic exposure | Poor | 14,600 | 1962 |
| I-55 (nb) over Sangamon River | Poor condition + traffic exposure | Poor | 14,600 | 1963 |
| I-55 SB over Sangamon River | Poor condition + traffic exposure | Poor | 14,600 | 1963 |
| Fas 629 over Spring Creek | Poor condition + traffic exposure | Poor | 4,100 | 1974 |
| Il 123 over Fancy Creek | Poor condition + traffic exposure | Poor | 2,450 | 1919 |
| Ill 54 over Wolf Creek | Poor condition + traffic exposure | Poor | 2,150 | 1941 |
| Fas 631-cty HWY 31 over Wolf Creek | Poor condition + traffic exposure | Poor | 1,700 | 1985 |
| County HWY 37 over S Fork Sangamon Rive | Poor condition + traffic exposure | Poor | 1,600 | 1980 |
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.