US Bridges

Sierra HWY over Unnamed Wash

Poor

Los Angeles County, California · 2.0MI S/O Kern CO Line · Structure no. 53C0389

Built
1921
104 years old, rebuilt 1931
Condition
Poor
inspected June 2024
Type
Culvert
Concrete
Length
21 ft
2 main spans
Daily traffic
3,838
2017 count
Owner
County
County Highway Agency

About this bridge

Sierra HWY over Unnamed Wash is a concrete culvert carrying Sierra HWY over Unnamed Wash in Los Angeles County, California. It was built in 1921 and reconstructed in 1931, so it is 104 years old, older than the California average of 54.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 4 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

It carries about 3,838 vehicles a day, roughly 2% of them trucks, projected to reach 4,222 by 2043. The structure is 21 ft (6.4 m) long and 49 ft wide. If it were closed, the detour would be 6.8 mi (11 km).

Location

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CarriesSierra HWY
CrossesUnnamed Wash
Location2.0MI S/O Kern CO Line
RouteCounty Highway 0L639
CountyLos Angeles County
StateCalifornia
Coordinates34.79185, -118.15141
Functional classRural Minor Arterial

Condition and inspection

Poor

The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

ComponentRatingMeaning
Channel and channel protection9 ExcellentNo problems noted.
Culvert4 PoorAdvanced section loss, deterioration, spalling or scour.
Last inspectionJune 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment9: Superior to present desirable criteria
Operating rating44.6 US tons
Inventory rating26.8 US tons

Structure

Structure typeCulvert
MaterialConcrete
DeckNot applicable
Main spans2
Design loadUnknown
Structure length21 ft (6.4 m)
Longest span10 ft (3 m)
Deck width49 ft (14.9 m)
Roadway width25 ft (7.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,838 (2017)
Projected traffic4,222 by 2043
Trucks2%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.8 mi (11 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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$367,000 (2024 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Sierra HWY over Unnamed Wash built?

It was built in 1921, making it 104 years old in 2025. It was reconstructed in 1931.

What condition is Sierra HWY over Unnamed Wash in?

The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in June 2024.

How much traffic does Sierra HWY over Unnamed Wash carry?

About 3,838 vehicles per day (2017 count), of which roughly 2% are trucks.

How long is Sierra HWY over Unnamed Wash?

The structure is 21 ft (6.4 m) long with a longest span of 10 ft (3 m) and a deck 49 ft wide.

Who owns Sierra HWY over Unnamed Wash?

It is owned by the County Highway Agency.