Dorchester County Bridge Report Card

Dorchester County scores 85 out of 100 on BridgeLookup's Bridge Condition Exposure Score, based on FHWA National Bridge Inventory records.

B85 / 100

Local infrastructure snapshot

Dorchester County, South Carolina

Dorchester County has 199 bridges in the National Bridge Inventory, with 4 rated poor and 7 rated scour-critical. Its poor-condition share of 2.0% is at or below the 6.3% statewide average. Poor-condition bridges carry about 33,400 daily vehicle crossings.

199Total Bridges

4Poor (2.0%)

138Fair (69.3%)

7Scour-Critical

Quote-Ready Local Facts

2.0%of county bridges are in poor condition, compared with 6.3% statewide and 6.7% nationally.

33,400daily vehicle crossings are on poor-condition bridges in the county.

7bridges are rated scour-critical, or 3.5% of the county bridge inventory.

Copyable Facts for Reporters

BridgeLookup.com gives Dorchester County a Bridge Condition Exposure Score of 85/100 (B). The county has 199 bridges in the National Bridge Inventory, including 4 in poor condition and 7 rated scour-critical. Poor-condition bridges carry about 33,400 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	2.0%	4.0
Poor-condition traffic exposure	25	2.3% of measured traffic	1.7
Scour-critical bridge share	20	3.5%	7.0
Average age vs national baseline	10	54 years vs 48 nationally	2.3
Traffic-data completeness	5	1,439,030 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	2.0%
State Poor-Condition Share	6.3%
National Poor-Condition Share	6.7%
County Scour-Critical Share	3.5%
Average Bridge Age	54 years
Poor-Condition Traffic Exposure	33,400 vehicles/day

Bridges to Watch

Busiest Poor-Condition BridgeUS 17 Alt over Ashley River — 19,800 vehicles/day Oldest Listed BridgeUS 78/w 5th ST N over Great Cypress Swamp #3 — built in 1919 All County BridgesBrowse every bridge record in Dorchester County.

Top Bridges to Watch in Dorchester County

Bridge	Reason	Condition	Daily Traffic	Year Built
US 17 Alt over Ashley River	Poor condition + traffic exposure	Poor	19,800	1971
US 78 over Four Hole Swamp	Poor condition + traffic exposure	Poor	9,900	1948
US 15 over Edisto River	Poor condition + traffic exposure	Poor	2,700	1928
S-18-19/wire RD over Indian Fields Swamp	Poor condition + traffic exposure	Poor	1,000	1960
I-95 NB over Indian Field Swamp	Scour-critical foundation rating	Fair	25,800	1972
I-95 SB over Indian Field Swamp	Scour-critical foundation rating	Fair	25,800	1972
Sc 453/judge ST over Four Hole Swamp	Scour-critical foundation rating	Fair	3,900	1975
US 15 over Branch To Edisto River	Scour-critical foundation rating	Fair	2,700	1931
S-18-29 over Edisto River	Scour-critical foundation rating	Good	750	1980
S-18-18 over Cattle Creek	Scour-critical foundation rating	Fair	175	1994

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.