US Bridges

Boston Mill Road over I-5 (hwy 1)

Fair

Linn County, Oregon · 182 MI N Lane-Linn Line · Structure no. 08254 001 22158

Built
1958
67 years old
Condition
Fair
inspected December 2024
Type
Tee Beam
Concrete Continuous
Length
239 ft
4 main spans
Daily traffic
488
2010 count
Owner
State
State Highway Agency

About this bridge

Boston Mill Road over I-5 (hwy 1) is a concrete continuous tee beam carrying Boston Mill Road over I-5 (hwy 1) in Linn County, Oregon. It was built in 1958, so it is 67 years old, older than the Oregon average of 49.9 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.

It carries about 488 vehicles a day, roughly 5% of them trucks, projected to reach 667 by 2030. The structure is 239 ft (72.8 m) long and 29 ft wide. If it were closed, the detour would be 10.6 mi (17 km).

Location

Open in Google Maps
CarriesBoston Mill Road
CrossesI-5 (hwy 1)
Location182 MI N Lane-Linn Line
RouteCounty Highway 0
CountyLinn County
StateOregon
Coordinates44.46152, -123.06157
Functional classRural Major Collector

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.
Substructure8 Very GoodNo problems noted.
Last inspectionDecember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating28.5 US tons
Inventory rating22.2 US tons

Structure

Structure typeTee Beam
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20
Structure length239 ft (72.8 m)
Longest span76 ft (23.3 m)
Deck width29 ft (8.8 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic488 (2010)
Projected traffic667 by 2030
Trucks5%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesHighway
Detour if closed10.6 mi (17 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedWidening of existing bridge without deck rehabilitation
Estimated improvement cost$1.1 million
NavigationNot applicable (no waterway)

Frequently asked questions

When was Boston Mill Road over I-5 (hwy 1) built?

It was built in 1958, making it 67 years old in 2025.

What condition is Boston Mill Road over I-5 (hwy 1) 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 December 2024.

How much traffic does Boston Mill Road over I-5 (hwy 1) carry?

About 488 vehicles per day (2010 count), of which roughly 5% are trucks.

How long is Boston Mill Road over I-5 (hwy 1)?

The structure is 239 ft (72.8 m) long with a longest span of 76 ft (23.3 m) and a deck 29 ft wide.

Who owns Boston Mill Road over I-5 (hwy 1)?

It is owned by the State Highway Agency.