US Bridges

State Route 121 over Capell Creek

Good

Napa County, California · 04-NAP-121-20.29 · Structure no. 21 0112

Built
2014
11 years old
Condition
Good
inspected April 2024
Type
Slab
Prestressed Concrete
Length
63 ft
1 main span
Daily traffic
2,450
2009 count
Owner
State
State Highway Agency

About this bridge

State Route 121 over Capell Creek is a prestressed concrete slab carrying State Route 121 over Capell Creek in Napa County, California. It was built in 2014, so it is 11 years old, younger than the California average of 54.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 2,450 vehicles a day, roughly 3% of them trucks, projected to reach 1,116 by 2042. The structure is 63 ft (19.2 m) long and 44 ft wide. If it were closed, the detour would be 44.1 mi (71 km).

CarriesState Route 121
CrossesCapell Creek
Location04-NAP-121-20.29
RouteState Highway 121
Coordinates38.43043, -122.20867
Functional classRural Minor Arterial

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionApril 2024
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation7: Better than present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating46.4 US tons
Inventory rating35.7 US tons

Structure

Structure typeSlab
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHL 93
Structure length63 ft (19.2 m)
Longest span63 ft (19.2 m)
Deck width44 ft (13.4 m)
Roadway width41 ft (12.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,450 (2009)
Projected traffic1,116 by 2042
Trucks3%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed44.1 mi (71 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—
NavigationNo navigation control on waterway

Frequently asked questions

When was State Route 121 over Capell Creek built?

It was built in 2014, making it 11 years old in 2025.

What condition is State Route 121 over Capell Creek in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in April 2024.

How much traffic does State Route 121 over Capell Creek carry?

About 2,450 vehicles per day (2009 count), of which roughly 3% are trucks.

How long is State Route 121 over Capell Creek?

The structure is 63 ft (19.2 m) long with a longest span of 63 ft (19.2 m) and a deck 44 ft wide.

Who owns State Route 121 over Capell Creek?

It is owned by the State Highway Agency.