US Bridges

Ramp/Connector 101 over Colgan Creek

Fair

Sonoma County, California · 04-SON-101-18.91 · Structure no. 20 0196K

Built
1957
68 years old
Condition
Fair
inspected August 2024
Type
Culvert
Concrete Continuous
Length
22 ft
2 main spans
Daily traffic
2,400
2014 count
Owner
State
State Highway Agency

About this bridge

Ramp/Connector 101 over Colgan Creek is a concrete continuous culvert carrying Ramp/Connector 101 over Colgan Creek in Sonoma County, California. It was built in 1957, so it is 68 years old, older 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 2,400 vehicles a day, roughly 2% of them trucks, projected to reach 2,672 by 2046. The structure is 22 ft (6.7 m) long.

Location

Open in Google Maps
CarriesRamp/Connector 101
CrossesColgan Creek
Location04-SON-101-18.91
RouteU.S. Route 101
CountySonoma County
StateCalifornia
Coordinates38.42024, -122.71629
Functional classUrban Principal Arterial - Other Freeway or Expressway

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Channel and channel protection8 Very GoodNo problems noted.
Culvert6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionAugust 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating59.6 US tons
Inventory rating35.7 US tons

Structure

Structure typeCulvert
MaterialConcrete Continuous
DeckNot applicable
Main spans2
Design loadUnknown
Structure length22 ft (6.7 m)
Longest span10 ft (3 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,400 (2014)
Projected traffic2,672 by 2046
Trucks2%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
Detour if closed—
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

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 Ramp/Connector 101 over Colgan Creek built?

It was built in 1957, making it 68 years old in 2025.

What condition is Ramp/Connector 101 over Colgan 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 August 2024.

How much traffic does Ramp/Connector 101 over Colgan Creek carry?

About 2,400 vehicles per day (2014 count), of which roughly 2% are trucks.

How long is Ramp/Connector 101 over Colgan Creek?

The structure is 22 ft (6.7 m) long with a longest span of 10 ft (3 m).

Who owns Ramp/Connector 101 over Colgan Creek?

It is owned by the State Highway Agency.