US Bridges

Arnold Drive over Sonoma Creek

PoorPosted for load

Sonoma County, California · 7.6 MI North of SR 116 · Structure no. 20C0213

Built
1930
95 years old
Condition
Poor
inspected October 2024
Type
Truss - Thru
Steel
Length
143 ft
1 main span
Daily traffic
13,900
2015 count
Owner
County
County Highway Agency

About this bridge

Arnold Drive over Sonoma Creek is a steel truss - thru carrying Arnold Drive over Sonoma Creek in Sonoma County, California. It was built in 1930, so it is 95 years old, older than the California average of 54.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 4 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. Its operating status is: posted for load restriction.

It carries about 13,900 vehicles a day, roughly 5% of them trucks, projected to reach 14,486 by 2042. The structure is 143 ft (43.6 m) long and 26 ft wide. If it were closed, the detour would be 5 mi (8 km).

Location

Open in Google Maps
CarriesArnold Drive
CrossesSonoma Creek
Location7.6 MI North of SR 116
RouteCounty Highway 0
CountySonoma County
StateCalifornia
Coordinates38.35124, -122.51921
Functional classUrban Collector

Condition and inspection

Poor

The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

ComponentRatingMeaning
Deck4 PoorAdvanced section loss, deterioration, spalling or scour.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionOctober 2024
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation2: Basically intolerable, requiring high priority of replacement
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating21.4 US tons
Inventory rating12.9 US tons

Structure

Structure typeTruss - Thru
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadH 15
Structure length143 ft (43.6 m)
Longest span140 ft (42.7 m)
Deck width26 ft (7.8 m)
Roadway width24 ft (7.4 m)
Vertical clearance over deck13 ft (3.9 m)

Traffic and service

Average daily traffic13,900 (2015)
Projected traffic14,486 by 2042
Trucks5%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed5 mi (8 km)
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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$1.3 million (2025 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Arnold Drive over Sonoma Creek built?

It was built in 1930, making it 95 years old in 2025.

What condition is Arnold Drive over Sonoma Creek in?

The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in October 2024.

How much traffic does Arnold Drive over Sonoma Creek carry?

About 13,900 vehicles per day (2015 count), of which roughly 5% are trucks.

How long is Arnold Drive over Sonoma Creek?

The structure is 143 ft (43.6 m) long with a longest span of 140 ft (42.7 m) and a deck 26 ft wide.

Who owns Arnold Drive over Sonoma Creek?

It is owned by the County Highway Agency.