Carbon County Bridge Report Card

Carbon County scores 86 out of 100 on BridgeLookup's Bridge Condition Exposure Score, based on FHWA National Bridge Inventory records.

B86 / 100

Local infrastructure snapshot

Carbon County, Montana

Carbon County has 81 bridges in the National Bridge Inventory, with 4 rated poor and 1 rated scour-critical. Its poor-condition share of 4.9% is at or below the 7.4% statewide average. Poor-condition bridges carry about 731 daily vehicle crossings.

81Total Bridges

4Poor (4.9%)

46Fair (56.8%)

1Scour-Critical

Quote-Ready Local Facts

4.9%of county bridges are in poor condition, compared with 7.4% statewide and 6.7% nationally.

731daily vehicle crossings are on poor-condition bridges in the county.

1bridges are rated scour-critical, or 1.2% of the county bridge inventory.

Copyable Facts for Reporters

BridgeLookup.com gives Carbon County a Bridge Condition Exposure Score of 86/100 (B). The county has 81 bridges in the National Bridge Inventory, including 4 in poor condition and 1 rated scour-critical. Poor-condition bridges carry about 731 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	4.9%	9.9
Poor-condition traffic exposure	25	1.6% of measured traffic	1.2
Scour-critical bridge share	20	1.2%	2.5
Average age vs national baseline	10	40 years vs 48 nationally	0.0
Traffic-data completeness	5	44,408 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	4.9%
State Poor-Condition Share	7.4%
National Poor-Condition Share	6.7%
County Scour-Critical Share	1.2%
Average Bridge Age	40 years
Poor-Condition Traffic Exposure	731 vehicles/day

Bridges to Watch

Busiest Poor-Condition BridgeS 78 Fh 83 over Red Lodge Creek — 481 vehicles/day Oldest Listed BridgeLeslie RD over Elbow Creek 036 — built in 1913 All County BridgesBrowse every bridge record in Carbon County.

Top Bridges to Watch in Carbon County

Bridge	Reason	Condition	Daily Traffic	Year Built
Willow Creek RD over Willow Creek 061	Poor condition + traffic exposure	Poor	100	1942
S 78 Fh 83 over Red Lodge Creek	Poor condition + traffic exposure	Poor	481	1953
W Pryor RD over Elbow Creek 037	Poor condition + traffic exposure	Poor	100	1964
2-lane Road over Rock Creek	Poor condition + traffic exposure	Poor	50	1970
US 310 over Sand Creek	High traffic	Good	4,907	1987
US 310 over Rock Creek	High traffic	Fair	4,561	1934
US 212 over Rock Creek	High traffic	Fair	3,817	1974
US 212 over Rock Creek	High traffic	Good	2,491	2001
US 310 over Bridger Creek	High traffic	Fair	1,932	1971
US 310 over Clarks Fk Yellowstone	High traffic	Fair	1,932	1971

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.