US Bridges

Old Redwood HWY over Windsor Creek

Fair

Sonoma County, California · 100 Yards West of RTE 101 · Structure no. 20C0507

Built
1995
30 years old
Condition
Fair
inspected July 2023
Type
Box Beam or Girders - Multiple
Prestressed Concrete
Length
72 ft
1 main span
Daily traffic
2,000
2011 count
Owner
Town / Township
Town or Township Highway Agency

About this bridge

Old Redwood HWY over Windsor Creek is a prestressed concrete box beam or girders - multiple carrying Old Redwood HWY over Windsor Creek in Sonoma County, California. It was built in 1995, so it is 30 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 6 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 2,000 vehicles a day, roughly 5% of them trucks, projected to reach 6,564 by 2045. The structure is 72 ft (22 m) long and 102 ft wide. If it were closed, the detour would be 6.2 mi (10 km).

Location

Open in Google Maps
CarriesOld Redwood HWY
CrossesWindsor Creek
Location100 Yards West of RTE 101
RouteCity Street 0
CountySonoma County
StateCalifornia
Coordinates38.54727, -122.80987
Functional classUrban 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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
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
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20 + Mod
Structure length72 ft (22 m)
Longest span70 ft (21.2 m)
Deck width102 ft (31.2 m)
Roadway width69 ft (21 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,000 (2011)
Projected traffic6,564 by 2045
Trucks5%
Lanes on structure5
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed6.2 mi (10 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerTown or Township Highway Agency
Maintained byTown or Township 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 Redwood HWY over Windsor Creek built?

It was built in 1995, making it 30 years old in 2025.

What condition is Old Redwood HWY over Windsor 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 July 2023.

How much traffic does Old Redwood HWY over Windsor Creek carry?

About 2,000 vehicles per day (2011 count), of which roughly 5% are trucks.

How long is Old Redwood HWY over Windsor Creek?

The structure is 72 ft (22 m) long with a longest span of 70 ft (21.2 m) and a deck 102 ft wide.

Who owns Old Redwood HWY over Windsor Creek?

It is owned by the Town or Township Highway Agency.