St. Clair County Bridge Report Card

St. Clair County scores 73 out of 100 on BridgeLookup's Bridge Condition Exposure Score, based on FHWA National Bridge Inventory records.

C73 / 100

Local infrastructure snapshot

St. Clair County, Illinois

St. Clair County has 485 bridges in the National Bridge Inventory, with 45 rated poor and 2 rated scour-critical. Its poor-condition share of 9.3% is at or below the 9.5% statewide average. Poor-condition bridges carry about 538,925 daily vehicle crossings.

485Total Bridges

45Poor (9.3%)

205Fair (42.3%)

2Scour-Critical

Quote-Ready Local Facts

9.3%of county bridges are in poor condition, compared with 9.5% statewide and 6.7% nationally.

538,925daily vehicle crossings are on poor-condition bridges in the county.

2bridges are rated scour-critical, or 0.4% of the county bridge inventory.

Copyable Facts for Reporters

BridgeLookup.com gives St. Clair County a Bridge Condition Exposure Score of 73/100 (C). The county has 485 bridges in the National Bridge Inventory, including 45 in poor condition and 2 rated scour-critical. Poor-condition bridges carry about 538,925 daily vehicle crossings. Poor condition does not mean unsafe; bridges judged unsafe are closed or restricted by transportation agencies.

Download all county report-card scores as CSV.

How the Score Breaks Down

Factor	Weight	County Value	Penalty
Poor-condition bridge share	40	9.3%	18.6
Poor-condition traffic exposure	25	10.2% of measured traffic	7.7
Scour-critical bridge share	20	0.4%	0.8
Average age vs national baseline	10	48 years vs 48 nationally	0.0
Traffic-data completeness	5	5,270,580 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	9.3%
State Poor-Condition Share	9.5%
National Poor-Condition Share	6.7%
County Scour-Critical Share	0.4%
Average Bridge Age	48 years
Poor-Condition Traffic Exposure	538,925 vehicles/day

Bridges to Watch

Busiest Poor-Condition BridgeI-55/64; US 40 Psc over Trra — 113,200 vehicles/day Oldest Listed BridgeFau 9187a & Met Li over Miss Riv/rr/mss6000 — built in 1874 All County BridgesBrowse every bridge record in St. Clair County.

Top Bridges to Watch in St. Clair County

Bridge	Reason	Condition	Daily Traffic	Year Built
I-55/64; US 40 Psc over Trra	Poor condition + traffic exposure	Poor	113,200	1966
I-55/70;/64 over Csxrr Nsrr Trrarr	Poor condition + traffic exposure	Poor	66,500	1959
Fai 255 over Ill 15	Poor condition + traffic exposure	Poor	44,300	1981
I-255 over Nsrr	Poor condition + traffic exposure	Poor	41,500	1980
Fai 255 over Ill 163	Poor condition + traffic exposure	Poor	41,500	1980
I-55/70 & US 40 EB over Drainage Canal	Poor condition + traffic exposure	Poor	33,250	1960
Fai 255 over Stolle RD Fau 9208	Poor condition + traffic exposure	Poor	31,400	1979
I-64 EB over Nsrr	Poor condition + traffic exposure	Poor	15,500	1971
I-64 WB over Nsrr	Poor condition + traffic exposure	Poor	15,500	1971
Il 111 over A&srr	Poor condition + traffic exposure	Poor	13,900	1973

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.