US Bridges

Auto Tour Route over Main Drain

Fair

Colusa County, California · W .8 MI on Refuge Road · Structure no. 000011621-00159

Built
1976
49 years old
Condition
Fair
inspected October 2024
Type
Tee Beam
Prestressed Concrete
Length
143 ft
3 main spans
Daily traffic
25
2024 count
Owner
Federal
Bureau of Fish and Wildlife

About this bridge

Auto Tour Route over Main Drain is a prestressed concrete tee beam carrying Auto Tour Route over Main Drain in Colusa County, California. It was built in 1976, so it is 49 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 25 vehicles a day, projected to reach 30 by 2044. The structure is 143 ft (43.6 m) long and 16 ft wide. If it were closed, the detour would be 98.8 mi (159 km).

Location

Open in Google Maps
CarriesAuto Tour Route
CrossesMain Drain
LocationW .8 MI on Refuge Road
RouteFederal Lands Road 0
CountyColusa County
StateCalifornia
Coordinates39.18317, -122.0515
Functional classRural Local

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.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionOctober 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; action required to protect exposed foundations
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry6: Equal to present minimum criteria
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment5: Somewhat better than minimum adequacy to tolerate being left in place as is
Operating rating36 US tons
Inventory rating27 US tons

Structure

Structure typeTee Beam
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadUnknown
Structure length143 ft (43.6 m)
Longest span47 ft (14.3 m)
Deck width16 ft (4.9 m)
Roadway width14 ft (4.3 m)
Vertical clearance over deck107 ft (32.7 m)

Traffic and service

Average daily traffic25 (2024)
Projected traffic30 by 2044
Trucks0%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed98.8 mi (159 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerBureau of Fish and Wildlife
Maintained byBureau of Fish and Wildlife
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 Auto Tour Route over Main Drain built?

It was built in 1976, making it 49 years old in 2025.

What condition is Auto Tour Route over Main Drain 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 October 2024.

How much traffic does Auto Tour Route over Main Drain carry?

About 25 vehicles per day (2024 count).

How long is Auto Tour Route over Main Drain?

The structure is 143 ft (43.6 m) long with a longest span of 47 ft (14.3 m) and a deck 16 ft wide.

Who owns Auto Tour Route over Main Drain?

It is owned by the Bureau of Fish and Wildlife.