US Bridges

Alderbrook DR over Santa Rosa Creek

Good

Sonoma County, California · Near 4th Street · Structure no. 20C0189

Built
1979
46 years old
Condition
Good
inspected August 2022
Type
Slab
Concrete Continuous
Length
102 ft
3 main spans
Daily traffic
1,000
2010 count
Owner
City
City or Municipal Highway Agency

About this bridge

Alderbrook DR over Santa Rosa Creek is a concrete continuous slab carrying Alderbrook DR over Santa Rosa Creek in Sonoma County, California. It was built in 1979, so it is 46 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 1,000 vehicles a day, roughly 2% of them trucks, projected to reach 1,615 by 2044. The structure is 102 ft (31.1 m) long and 36 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesAlderbrook DR
CrossesSanta Rosa Creek
LocationNear 4th Street
RouteCity Street 0
CountySonoma County
StateCalifornia
Coordinates38.44933, -122.69817
Functional classUrban Other Principal 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 protection8 Very GoodNo problems noted.
Last inspectionAugust 2022
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment3: Basically intolerable, requiring high priority of corrective action
Operating rating65 US tons
Inventory rating50.4 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length102 ft (31.1 m)
Longest span40 ft (12.2 m)
Deck width36 ft (11 m)
Roadway width30 ft (9.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,000 (2010)
Projected traffic1,615 by 2044
Trucks2%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed3.7 mi (6 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal 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 Alderbrook DR over Santa Rosa Creek built?

It was built in 1979, making it 46 years old in 2025.

What condition is Alderbrook DR over Santa Rosa 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 August 2022.

How much traffic does Alderbrook DR over Santa Rosa Creek carry?

About 1,000 vehicles per day (2010 count), of which roughly 2% are trucks.

How long is Alderbrook DR over Santa Rosa Creek?

The structure is 102 ft (31.1 m) long with a longest span of 40 ft (12.2 m) and a deck 36 ft wide.

Who owns Alderbrook DR over Santa Rosa Creek?

It is owned by the City or Municipal Highway Agency.