St. Clair County Bridge Report Card

St. Clair County scores 77 out of 100 on BridgeLookup's Bridge Condition Exposure Score, based on FHWA National Bridge Inventory records.

C77 / 100

Local infrastructure snapshot

St. Clair County, Michigan

St. Clair County has 326 bridges in the National Bridge Inventory, with 31 rated poor and 3 rated scour-critical. Its poor-condition share of 9.5% is at or below the 11.0% statewide average. Poor-condition bridges carry about 40,068 daily vehicle crossings.

326Total Bridges

31Poor (9.5%)

165Fair (50.6%)

3Scour-Critical

Quote-Ready Local Facts

9.5%of county bridges are in poor condition, compared with 11.0% statewide and 6.7% nationally.

40,068daily vehicle crossings are on poor-condition bridges in the county.

3bridges are rated scour-critical, or 0.9% of the county bridge inventory.

Copyable Facts for Reporters

BridgeLookup.com gives St. Clair County a Bridge Condition Exposure Score of 77/100 (C). The county has 326 bridges in the National Bridge Inventory, including 31 in poor condition and 3 rated scour-critical. Poor-condition bridges carry about 40,068 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	9.5%	19.0
Poor-condition traffic exposure	25	3.1% of measured traffic	2.3
Scour-critical bridge share	20	0.9%	1.8
Average age vs national baseline	10	40 years vs 48 nationally	0.0
Traffic-data completeness	5	1,289,667 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	9.5%
State Poor-Condition Share	11.0%
National Poor-Condition Share	6.7%
County Scour-Critical Share	0.9%
Average Bridge Age	40 years
Poor-Condition Traffic Exposure	40,068 vehicles/day

Bridges to Watch

Busiest Poor-Condition BridgeI-94 WB over M-25 Conn — 21,619 vehicles/day Oldest Listed BridgeRavenswood Road over Smiths Creek — built in 1912 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-94 WB over M-25 Conn	Poor condition + traffic exposure	Poor	21,619	1964
Yale Road over S Br Mill Creek Drain	Poor condition + traffic exposure	Poor	2,602	1989
Shea Road over Beaubien Creek Drain	Poor condition + traffic exposure	Poor	2,500	1963
Griswold Road over Pine River	Poor condition + traffic exposure	Poor	2,030	1990
Anchor Bay Drive over Unnamed Canal	Poor condition + traffic exposure	Poor	1,655	1980
Sparling Road over Pine River	Poor condition + traffic exposure	Poor	1,390	1988
Broadbridge Road over Marine City Dredge Cut	Poor condition + traffic exposure	Poor	1,100	1986
Yale Road over Eves Drain	Poor condition + traffic exposure	Poor	980	1922
Allen RD over I-69	Poor condition + traffic exposure	Poor	883	1966
Allington RD over I-94	Poor condition + traffic exposure	Poor	690	1964

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.