US Bridges

NE Carn. Farm RD over Slough

Good

King County, Washington · 0.2 MI W of SR-203 · Structure no. 086382000000000

Built
1998
27 years old
Condition
Good
inspected June 2023
Type
Slab
Prestressed Concrete
Length
40 ft
1 main span
Daily traffic
1,259
2021 count
Owner
County
County Highway Agency

About this bridge

NE Carn. Farm RD over Slough is a prestressed concrete slab carrying NE Carn. Farm RD over Slough in King County, Washington. It was built in 1998, so it is 27 years old, younger than the Washington average of 49.8 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 1,259 vehicles a day, roughly 10% of them trucks, projected to reach 2,275 by 2041. The structure is 40 ft (12.2 m) long and 36 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

CarriesNE Carn. Farm RD
CrossesSlough
Location0.2 MI W of SR-203
RouteCounty Highway 96806
Coordinates47.66271, -121.91345
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.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionJune 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating86.4 US tons
Inventory rating65.7 US tons

Structure

Structure typeSlab
MaterialPrestressed Concrete
DeckConcrete, precast panels
Main spans1
Design loadHS 25 or greater
Structure length40 ft (12.2 m)
Longest span39 ft (11.9 m)
Deck width36 ft (11 m)
Roadway width34 ft (10.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,259 (2021)
Projected traffic2,275 by 2041
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedWidening of existing bridge without deck rehabilitation
Estimated improvement cost$684,000 (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was NE Carn. Farm RD over Slough built?

It was built in 1998, making it 27 years old in 2025.

What condition is NE Carn. Farm RD over 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 June 2023.

How much traffic does NE Carn. Farm RD over Slough carry?

About 1,259 vehicles per day (2021 count), of which roughly 10% are trucks.

How long is NE Carn. Farm RD over Slough?

The structure is 40 ft (12.2 m) long with a longest span of 39 ft (11.9 m) and a deck 36 ft wide.

Who owns NE Carn. Farm RD over Slough?

It is owned by the County Highway Agency.