US Bridges

State Route 20 over Squirrel Creek

Good

Nevada County, California · 03-NEV-020-R6.55 · Structure no. 17 0094

Built
1984
41 years old
Condition
Good
inspected June 2022
Type
Slab
Concrete Continuous
Length
84 ft
1 main span
Daily traffic
13,000
2020 count
Owner
State
State Highway Agency

About this bridge

State Route 20 over Squirrel Creek is a concrete continuous slab carrying State Route 20 over Squirrel Creek in Nevada County, California. It was built in 1984, so it is 41 years old, younger than the California average of 54.8 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 13,000 vehicles a day, projected to reach 21,567 by 2041. The structure is 84 ft (25.6 m) long and 79 ft wide. If it were closed, the detour would be 14.3 mi (23 km).

Location

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CarriesState Route 20
CrossesSquirrel Creek
Location03-NEV-020-R6.55
RouteState Highway 20
CountyNevada County
StateCalifornia
Coordinates39.20319, -121.17061
Functional classUrban Principal Arterial - Other Freeway or Expressway

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 2022
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating59.6 US tons
Inventory rating35.7 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length84 ft (25.6 m)
Longest span42 ft (12.8 m)
Deck width79 ft (24.2 m)
Roadway width76 ft (23.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic13,000 (2020)
Projected traffic21,567 by 2041
Trucks0%
Lanes on structure5
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed14.3 mi (23 km)
TollOn a free road
National Highway SystemYes

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 Squirrel Creek built?

It was built in 1984, making it 41 years old in 2025.

What condition is State Route 20 over Squirrel Creek 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 2022.

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

About 13,000 vehicles per day (2020 count).

How long is State Route 20 over Squirrel Creek?

The structure is 84 ft (25.6 m) long with a longest span of 42 ft (12.8 m) and a deck 79 ft wide.

Who owns State Route 20 over Squirrel Creek?

It is owned by the State Highway Agency.