US Bridges

Mack RD over Sumas River

FairPosted for load

Whatcom County, Washington · 00.2 W Oat Coles RD · Structure no. 080909000000000

Built
1932
93 years old, rebuilt 2002
Condition
Fair
inspected October 2023
Type
Channel Beam
Concrete
Length
31 ft
1 main span
Daily traffic
106
2021 count
Owner
County
County Highway Agency

About this bridge

Mack RD over Sumas River is a concrete channel beam carrying Mack RD over Sumas River in Whatcom County, Washington. It was built in 1932 and reconstructed in 2002, so it is 93 years old, older than the Washington average of 49.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. Its operating status is: posted for load restriction.

It carries about 106 vehicles a day, roughly 12% of them trucks, projected to reach 180 by 2043. The structure is 31 ft (9.4 m) long and 26 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

Open in Google Maps
CarriesMack RD
CrossesSumas River
Location00.2 W Oat Coles RD
RouteCounty Highway 65940
CountyWhatcom County
StateWashington
Coordinates48.89167, -122.305
Functional classRural Local

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionOctober 2023
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating24 US tons
Inventory rating14 US tons

Structure

Structure typeChannel Beam
MaterialConcrete
DeckOther
Main spans1
Design loadH 20
Structure length31 ft (9.4 m)
Longest span31 ft (9.4 m)
Deck width26 ft (7.8 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic106 (2021)
Projected traffic180 by 2043
Trucks12%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.1 mi (5 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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$1.5 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Mack RD over Sumas River built?

It was built in 1932, making it 93 years old in 2025. It was reconstructed in 2002.

What condition is Mack RD over Sumas River in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in October 2023.

How much traffic does Mack RD over Sumas River carry?

About 106 vehicles per day (2021 count), of which roughly 12% are trucks.

How long is Mack RD over Sumas River?

The structure is 31 ft (9.4 m) long with a longest span of 31 ft (9.4 m) and a deck 26 ft wide.

Who owns Mack RD over Sumas River?

It is owned by the County Highway Agency.