US Bridges

W37-S101&N101 Off over County RD US 101 Nwprr

Fair

Marin County, California · 04-MRN-037-R11.20-NVTO · Structure no. 27 0081H

Built
1964
61 years old
Condition
Fair
inspected May 2024
Type
Box Beam or Girders - Multiple
Concrete Continuous
Length
1,059 ft
13 main spans
Daily traffic
18,000
2004 count
Owner
State
State Highway Agency

About this bridge

W37-S101&N101 Off over County RD US 101 Nwprr is a concrete continuous box beam or girders - multiple carrying W37-S101&N101 Off over County RD US 101 Nwprr in Marin County, California. It was built in 1964, so it is 61 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 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 18,000 vehicles a day, roughly 2% of them trucks, projected to reach 29,051 by 2046. The structure is 1,059 ft (322.8 m) long and 36 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

Open in Google Maps
CarriesW37-S101&N101 Off
CrossesCounty RD US 101 Nwprr
Location04-MRN-037-R11.20-NVTO
RouteState Highway 37
CountyMarin County
StateCalifornia
Coordinates38.07953, -122.54635
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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Last inspectionMay 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation7: Better than present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment6: Equal to present minimum criteria
Operating rating85.8 US tons
Inventory rating51.5 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans13
Design loadHS 20 + Mod
Structure length1,059 ft (322.8 m)
Longest span102 ft (31.1 m)
Deck width36 ft (11 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic18,000 (2004)
Projected traffic29,051 by 2046
Trucks2%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway and railroad
Detour if closed3.1 mi (5 km)
TollOn a free road
National Highway SystemYes

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 W37-S101&N101 Off over County RD US 101 Nwprr built?

It was built in 1964, making it 61 years old in 2025.

What condition is W37-S101&N101 Off over County RD US 101 Nwprr 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 May 2024.

How much traffic does W37-S101&N101 Off over County RD US 101 Nwprr carry?

About 18,000 vehicles per day (2004 count), of which roughly 2% are trucks.

How long is W37-S101&N101 Off over County RD US 101 Nwprr?

The structure is 1,059 ft (322.8 m) long with a longest span of 102 ft (31.1 m) and a deck 36 ft wide.

Who owns W37-S101&N101 Off over County RD US 101 Nwprr?

It is owned by the State Highway Agency.