US Bridges

Twin Firs Lane over Potter Creek

Fair

Lane County, Oregon · 130 MI E Springfield · Structure no. 39C116107800015

Built
1981
44 years old
Condition
Fair
inspected August 2024
Type
Slab
Prestressed Concrete
Length
28 ft
1 main span
Daily traffic
196
2020 count
Owner
County
County Highway Agency

About this bridge

Twin Firs Lane over Potter Creek is a prestressed concrete slab carrying Twin Firs Lane over Potter Creek in Lane County, Oregon. It was built in 1981, so it is 44 years old, younger 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 196 vehicles a day, roughly 10% of them trucks, projected to reach 231 by 2025. The structure is 28 ft (8.5 m) long and 28 ft wide. If it were closed, the detour would be 123.7 mi (199 km).

Location

Open in Google Maps
CarriesTwin Firs Lane
CrossesPotter Creek
Location130 MI E Springfield
RouteCounty Highway C1078
CountyLane County
StateOregon
Coordinates44.0805, -122.75931
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
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionAugust 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourUnknown foundation; not evaluated for scour
Structural evaluation6: Equal to present minimum criteria
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 rating73 US tons
Inventory rating44 US tons

Structure

Structure typeSlab
MaterialPrestressed Concrete
DeckOther
Main spans1
Design loadHS 20
Structure length28 ft (8.5 m)
Longest span27 ft (8.2 m)
Deck width28 ft (8.5 m)
Roadway width28 ft (8.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic196 (2020)
Projected traffic231 by 2025
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
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—
NavigationNo navigation control on waterway

Frequently asked questions

When was Twin Firs Lane over Potter Creek built?

It was built in 1981, making it 44 years old in 2025.

What condition is Twin Firs Lane over Potter Creek 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 August 2024.

How much traffic does Twin Firs Lane over Potter Creek carry?

About 196 vehicles per day (2020 count), of which roughly 10% are trucks.

How long is Twin Firs Lane over Potter Creek?

The structure is 28 ft (8.5 m) long with a longest span of 27 ft (8.2 m) and a deck 28 ft wide.

Who owns Twin Firs Lane over Potter Creek?

It is owned by the County Highway Agency.