US Bridges

State Route 20 over Middle Creek

Fair

Lake County, California · 01-LAK-020-8.56 · Structure no. 14 0002

Built
1959
66 years old
Condition
Fair
inspected October 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
219 ft
3 main spans
Daily traffic
8,000
2009 count
Owner
State
State Highway Agency

About this bridge

State Route 20 over Middle Creek is a prestressed concrete stringer/multi-beam or girder carrying State Route 20 over Middle Creek in Lake County, California. It was built in 1959, so it is 66 years old, older than the California average of 54.8 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.

It carries about 8,000 vehicles a day, roughly 10% of them trucks, projected to reach 12,144 by 2046. The structure is 219 ft (66.8 m) long and 40 ft wide. If it were closed, the detour would be 9.9 mi (16 km).

Location

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CarriesState Route 20
CrossesMiddle Creek
Location01-LAK-020-8.56
RouteState Highway 20
CountyLake County
StateCalifornia
Coordinates39.16342, -122.91659
Functional classRural Minor Arterial

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.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionOctober 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
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
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating43.5 US tons
Inventory rating23.3 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length219 ft (66.8 m)
Longest span72 ft (21.9 m)
Deck width40 ft (12.3 m)
Roadway width32 ft (9.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic8,000 (2009)
Projected traffic12,144 by 2046
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed9.9 mi (16 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 proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was State Route 20 over Middle Creek built?

It was built in 1959, making it 66 years old in 2025.

What condition is State Route 20 over Middle 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 October 2024.

How much traffic does State Route 20 over Middle Creek carry?

About 8,000 vehicles per day (2009 count), of which roughly 10% are trucks.

How long is State Route 20 over Middle Creek?

The structure is 219 ft (66.8 m) long with a longest span of 72 ft (21.9 m) and a deck 40 ft wide.

Who owns State Route 20 over Middle Creek?

It is owned by the State Highway Agency.