US Bridges

US 278 WB over Palmetto Lagoon

Good

Beaufort County, South Carolina · Hilton Head Island · Structure no. 000000000009556

Built
2001
24 years old
Condition
Good
inspected July 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete Continuous
Length
120 ft
3 main spans
Daily traffic
13,600
2023 count
Owner
State
State Highway Agency

About this bridge

US 278 WB over Palmetto Lagoon is a prestressed concrete continuous stringer/multi-beam or girder carrying US 278 WB over Palmetto Lagoon in Beaufort County, South Carolina. It was built in 2001, so it is 24 years old, younger than the South Carolina average of 48 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 13,600 vehicles a day, roughly 3% of them trucks, projected to reach 16,320 by 2043. The structure is 120 ft (36.6 m) long and 47 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

CarriesUS 278 WB
CrossesPalmetto Lagoon
LocationHilton Head Island
RouteU.S. Route 278
Coordinates32.18011, -80.72455
Functional classUrban Other Principal Arterial

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionJuly 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry9: Superior to present desirable criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating74.3 US tons
Inventory rating44.3 US tons

Structure

MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 25 or greater
Structure length120 ft (36.6 m)
Longest span40 ft (12.2 m)
Deck width47 ft (14.4 m)
Roadway width44 ft (13.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic13,600 (2023)
Projected traffic16,320 by 2043
Trucks3%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedWidening with deck rehabilitation or replacement
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was US 278 WB over Palmetto Lagoon built?

It was built in 2001, making it 24 years old in 2025.

What condition is US 278 WB over Palmetto Lagoon in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in July 2024.

How much traffic does US 278 WB over Palmetto Lagoon carry?

About 13,600 vehicles per day (2023 count), of which roughly 3% are trucks.

How long is US 278 WB over Palmetto Lagoon?

The structure is 120 ft (36.6 m) long with a longest span of 40 ft (12.2 m) and a deck 47 ft wide.

Who owns US 278 WB over Palmetto Lagoon?

It is owned by the State Highway Agency.