US Bridges

US Highway 101 SB over Lytton Springs Road

Fair

Sonoma County, California · 04-SON-101-R38.56 · Structure no. 20 0233L

Built
1974
51 years old
Condition
Fair
inspected April 2023
Type
Box Beam or Girders - Multiple
Prestressed Concrete
Length
163 ft
1 main span
Daily traffic
13,500
2015 count
Owner
State
State Highway Agency

About this bridge

US Highway 101 SB over Lytton Springs Road is a prestressed concrete box beam or girders - multiple carrying US Highway 101 SB over Lytton Springs Road 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 25,314 by 2045. The structure is 163 ft (49.7 m) long and 41 ft wide.

CarriesUS Highway 101 SB
CrossesLytton Springs Road
Location04-SON-101-R38.56
RouteU.S. Route 101
Coordinates38.65939, -122.87448
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.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
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 rating56.8 US tons
Inventory rating35.4 US tons

Structure

MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length163 ft (49.7 m)
Longest span161 ft (49.1 m)
Deck width41 ft (12.5 m)
Roadway width39 ft (11.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic13,500 (2015)
Projected traffic25,314 by 2045
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 Lytton Springs Road built?

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

What condition is US Highway 101 SB over Lytton Springs Road 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 Lytton Springs Road carry?

About 13,500 vehicles per day (2015 count), of which roughly 11% are trucks.

How long is US Highway 101 SB over Lytton Springs Road?

The structure is 163 ft (49.7 m) long with a longest span of 161 ft (49.1 m) and a deck 41 ft wide.

Who owns US Highway 101 SB over Lytton Springs Road?

It is owned by the State Highway Agency.