US Bridges

Old HWY 99 South over Guys Gulch

Fair

Siskiyou County, California · 1.1 MI NW of 99-97 Cutoff · Structure no. 02C0285

Built
2019
6 years old
Condition
Fair
inspected May 2024
Type
Slab
Concrete
Length
36 ft
1 main span
Daily traffic
1,000
2024 count
Owner
County
County Highway Agency

About this bridge

Old HWY 99 South over Guys Gulch is a concrete slab carrying Old HWY 99 South over Guys Gulch in Siskiyou County, California. It was built in 2019, so it is 6 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 1,000 vehicles a day, roughly 3% of them trucks, projected to reach 1,300 by 2044. The structure is 36 ft (10.9 m) long and 33 ft wide.

Location

Open in Google Maps
CarriesOld HWY 99 South
CrossesGuys Gulch
Location1.1 MI NW of 99-97 Cutoff
RouteCounty Highway 0
CountySiskiyou County
StateCalifornia
Coordinates41.65239, -122.55753
Functional classRural Major Collector

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.
Channel and channel protection7 GoodSome minor problems.
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 geometry6: Equal to present minimum criteria
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating59.6 US tons
Inventory rating35.7 US tons

Structure

Structure typeSlab
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadHL 93
Structure length36 ft (10.9 m)
Longest span33 ft (10.2 m)
Deck width33 ft (10.2 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,000 (2024)
Projected traffic1,300 by 2044
Trucks3%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed—
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—
NavigationNot applicable (no waterway)

Frequently asked questions

When was Old HWY 99 South over Guys Gulch built?

It was built in 2019, making it 6 years old in 2025.

What condition is Old HWY 99 South over Guys Gulch 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 Old HWY 99 South over Guys Gulch carry?

About 1,000 vehicles per day (2024 count), of which roughly 3% are trucks.

How long is Old HWY 99 South over Guys Gulch?

The structure is 36 ft (10.9 m) long with a longest span of 33 ft (10.2 m) and a deck 33 ft wide.

Who owns Old HWY 99 South over Guys Gulch?

It is owned by the County Highway Agency.