US Bridges

US Highway 101 SB over Souverain RD

Fair

Sonoma County, California · 04-SON-101-R40.03 · Structure no. 20 0234L

Built
1974
51 years old
Condition
Fair
inspected April 2023
Type
Box Beam or Girders - Multiple
Prestressed Concrete
Length
115 ft
1 main span
Daily traffic
13,500
2019 count
Owner
State
State Highway Agency

About this bridge

US Highway 101 SB over Souverain RD is a prestressed concrete box beam or girders - multiple carrying US Highway 101 SB over Souverain RD in Sonoma County, California. It was built in 1974, so it is 51 years old, younger 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 5 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 13,500 vehicles a day, roughly 11% of them trucks, projected to reach 24,731 by 2041. The structure is 115 ft (35.1 m) long and 41 ft wide.

CarriesUS Highway 101 SB
CrossesSouverain RD
Location04-SON-101-R40.03
RouteU.S. Route 101
Coordinates38.67976, -122.88077
Functional classRural Principal Arterial - Other

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure7 GoodSome minor problems.
Last inspectionApril 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating46.1 US tons
Inventory rating34 US tons

Structure

MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length115 ft (35.1 m)
Longest span113 ft (34.4 m)
Deck width41 ft (12.5 m)
Roadway width39 ft (11.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic13,500 (2019)
Projected traffic24,731 by 2041
Trucks11%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
Detour if closed—
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

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—
NavigationNot applicable (no waterway)

Frequently asked questions

When was US Highway 101 SB over Souverain RD built?

It was built in 1974, making it 51 years old in 2025.

What condition is US Highway 101 SB over Souverain RD 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 April 2023.

How much traffic does US Highway 101 SB over Souverain RD carry?

About 13,500 vehicles per day (2019 count), of which roughly 11% are trucks.

How long is US Highway 101 SB over Souverain RD?

The structure is 115 ft (35.1 m) long with a longest span of 113 ft (34.4 m) and a deck 41 ft wide.

Who owns US Highway 101 SB over Souverain RD?

It is owned by the State Highway Agency.