US Bridges

Parnum Road (US20 over North Fork Cache Creek

Good

Lake County, California · 4.7 Miles NW of Clearlake · Structure no. 0000000L2132227

Built
2021
4 years old
Condition
Good
inspected April 2023
Type
Truss - Thru
Steel
Length
104 ft
1 main span
Daily traffic
1
2023 count
Owner
Federal
Bureau of Land Management

About this bridge

Parnum Road (US20 over North Fork Cache Creek is a steel truss - thru carrying Parnum Road (US20 over North Fork Cache Creek in Lake County, California. It was built in 2021, so it is 4 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 8 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. Its operating status is: new structure not yet open to traffic.

It carries about 1 vehicles a day, projected to reach 1 by 2040. The structure is 104 ft (31.6 m) long and 12 ft wide. If it were closed, the detour would be 123.7 mi (199 km).

Location

Open in Google Maps
CarriesParnum Road (US20
CrossesNorth Fork Cache Creek
Location4.7 Miles NW of Clearlake
RouteFederal Lands Road 0
CountyLake County
StateCalifornia
Coordinates39.00062, -122.55565
Functional classRural Local

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck8 Very GoodNo problems noted.
Superstructure8 Very GoodNo problems noted.
Substructure8 Very GoodNo problems noted.
Channel and channel protection7 GoodSome minor problems.
Last inspectionApril 2023
Inspection intervalevery 24 months
Operating statusNew structure not yet open to traffic
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation8: Equal to present desirable criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating46.4 US tons
Inventory rating35.7 US tons

Structure

Structure typeTruss - Thru
MaterialSteel
DeckSteel plate
Main spans1
Design loadHS 25 or greater
Structure length104 ft (31.6 m)
Longest span99 ft (30.2 m)
Deck width12 ft (3.8 m)
Roadway width12 ft (3.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1 (2023)
Projected traffic1 by 2040
Trucks—
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed123.7 mi (199 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerBureau of Land Management
Maintained byBureau of Land Management
Historic statusHistorical significance not determinable at this time
Work proposedOther structural work, including hydraulic replacements
Estimated improvement cost$4,000 (2021 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Parnum Road (US20 over North Fork Cache Creek built?

It was built in 2021, making it 4 years old in 2025.

What condition is Parnum Road (US20 over North Fork Cache 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 April 2023.

How much traffic does Parnum Road (US20 over North Fork Cache Creek carry?

About 1 vehicles per day (2023 count).

How long is Parnum Road (US20 over North Fork Cache Creek?

The structure is 104 ft (31.6 m) long with a longest span of 99 ft (30.2 m) and a deck 12 ft wide.

Who owns Parnum Road (US20 over North Fork Cache Creek?

It is owned by the Bureau of Land Management.