US Bridges

Bethel Island Road over Dutch Slough

Good

Contra Costa County, California · 1.5 MI N. of E Cypress RD · Structure no. 28C0489

Built
2010
15 years old
Condition
Good
inspected August 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete Continuous
Length
864 ft
6 main spans
Daily traffic
5,881
2013 count
Owner
County
County Highway Agency

About this bridge

Bethel Island Road over Dutch Slough is a prestressed concrete continuous stringer/multi-beam or girder carrying Bethel Island Road over Dutch Slough in Contra Costa County, California. It was built in 2010, so it is 15 years old, younger than the California average of 54.8 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 5,881 vehicles a day, roughly 5% of them trucks, projected to reach 8,782 by 2046. The structure is 864 ft (263.2 m) long and 45 ft wide. If it were closed, the detour would be 123.7 mi (199 km).

Location

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CarriesBethel Island Road
CrossesDutch Slough
Location1.5 MI N. of E Cypress RD
RouteCounty Highway 0
CountyContra Costa County
StateCalifornia
Coordinates38.01063, -121.64109
Functional classRural Major Collector

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.
Superstructure8 Very GoodNo problems noted.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionAugust 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation7: Better than present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating59.6 US tons
Inventory rating35.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans6 (+3 approach)
Design loadHS 20 + Mod
Structure length864 ft (263.2 m)
Longest span133 ft (40.5 m)
Deck width45 ft (13.8 m)
Roadway width33 ft (10.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic5,881 (2013)
Projected traffic8,782 by 2046
Trucks5%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesHighway and waterway
Detour if closed123.7 mi (199 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was Bethel Island Road over Dutch Slough built?

It was built in 2010, making it 15 years old in 2025.

What condition is Bethel Island Road over Dutch Slough 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 August 2024.

How much traffic does Bethel Island Road over Dutch Slough carry?

About 5,881 vehicles per day (2013 count), of which roughly 5% are trucks.

How long is Bethel Island Road over Dutch Slough?

The structure is 864 ft (263.2 m) long with a longest span of 133 ft (40.5 m) and a deck 45 ft wide.

Who owns Bethel Island Road over Dutch Slough?

It is owned by the County Highway Agency.