US Bridges

State Route 166 over Carrizo Creek

Fair

San Luis Obispo County, California · 05-SLO-166-44.26 · Structure no. 49 0041

Built
1941
84 years old
Condition
Fair
inspected May 2024
Type
Slab
Concrete Continuous
Length
46 ft
2 main spans
Daily traffic
2,900
2009 count
Owner
State
State Highway Agency

About this bridge

State Route 166 over Carrizo Creek is a concrete continuous slab carrying State Route 166 over Carrizo Creek in San Luis Obispo County, California. It was built in 1941, so it is 84 years old, older 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 2,900 vehicles a day, projected to reach 8,737 by 2042. The structure is 46 ft (14 m) long and 29 ft wide. If it were closed, the detour would be 123.7 mi (199 km).

Location

Open in Google Maps
CarriesState Route 166
CrossesCarrizo Creek
Location05-SLO-166-44.26
RouteState Highway 166
CountySan Luis Obispo County
StateCalifornia
Coordinates35.07178, -119.99561
Functional classRural Minor 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
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMay 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating27.4 US tons
Inventory rating21.1 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length46 ft (14 m)
Longest span23 ft (6.9 m)
Deck width29 ft (8.7 m)
Roadway width26 ft (7.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,900 (2009)
Projected traffic8,737 by 2042
Trucks0%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed123.7 mi (199 km)
TollOn a free road
National Highway SystemNo

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 State Route 166 over Carrizo Creek built?

It was built in 1941, making it 84 years old in 2025.

What condition is State Route 166 over Carrizo Creek 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 May 2024.

How much traffic does State Route 166 over Carrizo Creek carry?

About 2,900 vehicles per day (2009 count).

How long is State Route 166 over Carrizo Creek?

The structure is 46 ft (14 m) long with a longest span of 23 ft (6.9 m) and a deck 29 ft wide.

Who owns State Route 166 over Carrizo Creek?

It is owned by the State Highway Agency.