US Bridges

Trancas St-Redwood over State Route 29

Fair

Napa County, California · 04-NAP-029-13.00-NAP · Structure no. 21 0101

Built
2003
22 years old
Condition
Fair
inspected April 2023
Type
Box Beam or Girders - Multiple
Prestressed Concrete Continuous
Length
195 ft
2 main spans
Daily traffic
30,000
2009 count
Owner
State
State Highway Agency

About this bridge

Trancas St-Redwood over State Route 29 is a prestressed concrete continuous box beam or girders - multiple carrying Trancas St-Redwood over State Route 29 in Napa County, California. It was built in 2003, so it is 22 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 30,000 vehicles a day, roughly 5% of them trucks, projected to reach 48,944 by 2043. The structure is 195 ft (59.4 m) long and 104 ft wide. If it were closed, the detour would be 0.6 mi (1 km).

Location

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CarriesTrancas St-Redwood
CrossesState Route 29
Location04-NAP-029-13.00-NAP
RouteCity Street 0
CountyNapa County
StateCalifornia
Coordinates38.32114, -122.30882
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
Deck7 GoodSome minor problems.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure7 GoodSome minor problems.
Last inspectionApril 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating59.6 US tons
Inventory rating35.7 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20 + Mod
Structure length195 ft (59.4 m)
Longest span102 ft (31.2 m)
Deck width104 ft (31.8 m)
Roadway width93 ft (28.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic30,000 (2009)
Projected traffic48,944 by 2043
Trucks5%
Lanes on structure7
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesHighway
Detour if closed0.6 mi (1 km)
TollOn a free road
National Highway SystemYes

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 Trancas St-Redwood over State Route 29 built?

It was built in 2003, making it 22 years old in 2025.

What condition is Trancas St-Redwood over State Route 29 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 April 2023.

How much traffic does Trancas St-Redwood over State Route 29 carry?

About 30,000 vehicles per day (2009 count), of which roughly 5% are trucks.

How long is Trancas St-Redwood over State Route 29?

The structure is 195 ft (59.4 m) long with a longest span of 102 ft (31.2 m) and a deck 104 ft wide.

Who owns Trancas St-Redwood over State Route 29?

It is owned by the State Highway Agency.