Mariposa County Bridge Report Card

Mariposa County scores 48 out of 100 on BridgeLookup's Bridge Condition Exposure Score, based on FHWA National Bridge Inventory records.

F48 / 100

Local infrastructure snapshot

Mariposa County, California

Mariposa County has 109 bridges in the National Bridge Inventory, with 12 rated poor and 8 rated scour-critical. Its poor-condition share of 11.0% is above the 4.9% statewide average. Poor-condition bridges carry about 14,296 daily vehicle crossings.

109Total Bridges

12Poor (11.0%)

77Fair (70.6%)

8Scour-Critical

Quote-Ready Local Facts

11.0%of county bridges are in poor condition, compared with 4.9% statewide and 6.7% nationally.

14,296daily vehicle crossings are on poor-condition bridges in the county.

8bridges are rated scour-critical, or 7.3% of the county bridge inventory.

Copyable Facts for Reporters

BridgeLookup.com gives Mariposa County a Bridge Condition Exposure Score of 48/100 (F). The county has 109 bridges in the National Bridge Inventory, including 12 in poor condition and 8 rated scour-critical. Poor-condition bridges carry about 14,296 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	11.0%	22.0
Poor-condition traffic exposure	25	8.9% of measured traffic	6.7
Scour-critical bridge share	20	7.3%	14.7
Average age vs national baseline	10	69 years vs 48 nationally	8.6
Traffic-data completeness	5	160,009 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	11.0%
State Poor-Condition Share	4.9%
National Poor-Condition Share	6.7%
County Scour-Critical Share	7.3%
Average Bridge Age	69 years
Poor-Condition Traffic Exposure	14,296 vehicles/day

Bridges to Watch

Busiest Poor-Condition BridgeState Route 140 over Miles Creek — 4,650 vehicles/day Oldest Listed BridgeOak Grove Road over Striped Rock Creek — built in 1912 All County BridgesBrowse every bridge record in Mariposa County.

Top Bridges to Watch in Mariposa County

Bridge	Reason	Condition	Daily Traffic	Year Built
El Capitan Crossov over Merced River	Poor condition + traffic exposure	Poor	3,416	1933
Winding Road over Middle Miami Creek	Poor condition + traffic exposure	Poor	50	1965
Chowchilla Road over Big Creek	Poor condition + traffic exposure	Poor	20	1940
State Route 140 over Miles Creek	Poor condition + traffic exposure	Poor	4,650	1928
State Route 140 over Slate Gulch	Poor condition + traffic exposure	Poor	1,400	1926
State Route 140 over Sweetwater Creek	Poor condition + traffic exposure	Poor	1,400	1926
State Route 140 over South Fork Merced River	Poor condition + traffic exposure	Poor	1,400	1926
6th Street over Mariposa Creek	Poor condition + traffic exposure	Poor	1,080	1950
Triangle Road over Snow Creek	Poor condition + traffic exposure	Poor	360	1935
Buckeye Road over Mariposa Creek	Poor condition + traffic exposure	Poor	200	1947

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.