US Bridges

Hi Mountain RD over Arroyo Grande Creek

Fair

San Luis Obispo County, California · 1.5 MI E Lopez Cyn RD · Structure no. 49C0121

Built
1965
60 years old
Condition
Fair
inspected March 2023
Type
Tee Beam
Concrete
Length
57 ft
1 main span
Daily traffic
50
2010 count
Owner
County
County Highway Agency

About this bridge

Hi Mountain RD over Arroyo Grande Creek is a concrete tee beam carrying Hi Mountain RD over Arroyo Grande Creek in San Luis Obispo County, California. It was built in 1965, so it is 60 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 50 vehicles a day, projected to reach 81 by 2045. The structure is 57 ft (17.4 m) long and 25 ft wide. If it were closed, the detour would be 55.3 mi (89 km).

Location

Open in Google Maps
CarriesHi Mountain RD
CrossesArroyo Grande Creek
Location1.5 MI E Lopez Cyn RD
RouteCounty Highway 0
CountySan Luis Obispo County
StateCalifornia
Coordinates35.19002, -120.43455
Functional classRural Local

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.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionMarch 2023
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 geometry6: Equal to present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment3: Basically intolerable, requiring high priority of corrective action
Operating rating30.8 US tons
Inventory rating18.5 US tons

Structure

Structure typeTee Beam
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadUnknown
Structure length57 ft (17.4 m)
Longest span55 ft (16.8 m)
Deck width25 ft (7.6 m)
Roadway width24 ft (7.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic50 (2010)
Projected traffic81 by 2045
Trucks—
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed55.3 mi (89 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 proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Hi Mountain RD over Arroyo Grande Creek built?

It was built in 1965, making it 60 years old in 2025.

What condition is Hi Mountain RD over Arroyo Grande 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 March 2023.

How much traffic does Hi Mountain RD over Arroyo Grande Creek carry?

About 50 vehicles per day (2010 count).

How long is Hi Mountain RD over Arroyo Grande Creek?

The structure is 57 ft (17.4 m) long with a longest span of 55 ft (16.8 m) and a deck 25 ft wide.

Who owns Hi Mountain RD over Arroyo Grande Creek?

It is owned by the County Highway Agency.