US Bridges

US Highway 101 SB over Willow Road

Fair

San Luis Obispo County, California · 05-SLO-101-6.45 · Structure no. 49 0252L

Built
2012
13 years old
Condition
Fair
inspected January 2024
Type
Box Beam or Girders - Multiple
Prestressed Concrete
Length
147 ft
1 main span
Daily traffic
27,000
2009 count
Owner
State
State Highway Agency

About this bridge

US Highway 101 SB over Willow Road is a prestressed concrete box beam or girders - multiple carrying US Highway 101 SB over Willow Road in San Luis Obispo County, California. It was built in 2012, so it is 13 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 27,000 vehicles a day, roughly 21% of them trucks, projected to reach 54,320 by 2044. The structure is 147 ft (44.8 m) long and 42 ft wide. If it were closed, the detour would be 0.6 mi (1 km).

CarriesUS Highway 101 SB
CrossesWillow Road
Location05-SLO-101-6.45
RouteU.S. Route 101
Coordinates35.05506, -120.50105
Functional classUrban Other Principal Arterial

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.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Last inspectionJanuary 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation7: Better than present minimum criteria
Deck geometry7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating97.1 US tons
Inventory rating54.2 US tons

Structure

MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHL 93
Structure length147 ft (44.8 m)
Longest span142 ft (43.3 m)
Deck width42 ft (12.8 m)
Roadway width39 ft (11.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic27,000 (2009)
Projected traffic54,320 by 2044
Trucks21%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
Detour if closed0.6 mi (1 km)
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 Willow Road built?

It was built in 2012, making it 13 years old in 2025.

What condition is US Highway 101 SB over Willow 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 January 2024.

How much traffic does US Highway 101 SB over Willow Road carry?

About 27,000 vehicles per day (2009 count), of which roughly 21% are trucks.

How long is US Highway 101 SB over Willow Road?

The structure is 147 ft (44.8 m) long with a longest span of 142 ft (43.3 m) and a deck 42 ft wide.

Who owns US Highway 101 SB over Willow Road?

It is owned by the State Highway Agency.