US Bridges

U.S. Highway 101 over Nwp RR / Smart

Good

Marin County, California · 04-MRN-101-13.25-SRF · Structure no. 27 0002

Built
1957
68 years old, rebuilt 1987
Condition
Good
inspected March 2021
Type
Slab
Prestressed Concrete
Length
136 ft
3 main spans
Daily traffic
167,000
2009 count
Owner
State
State Highway Agency

About this bridge

U.S. Highway 101 over Nwp RR / Smart is a prestressed concrete slab carrying U.S. Highway 101 over Nwp RR / Smart in Marin County, California. It was built in 1957 and reconstructed in 1987, 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 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 167,000 vehicles a day, roughly 4% of them trucks, projected to reach 243,761 by 2038. The structure is 136 ft (41.6 m) long and 143 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

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CarriesU.S. Highway 101
CrossesNwp RR / Smart
Location04-MRN-101-13.25-SRF
RouteU.S. Route 101
CountyMarin County
StateCalifornia
Coordinates38.00139, -122.5372
Functional classUrban Principal Arterial - Other Freeway or Expressway

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.
Last inspectionMarch 2021
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation7: Better than present minimum criteria
Deck geometry9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating58.2 US tons
Inventory rating35.7 US tons

Structure

Structure typeSlab
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length136 ft (41.6 m)
Longest span45 ft (13.7 m)
Deck width143 ft (43.7 m)
Roadway width137 ft (41.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic167,000 (2009)
Projected traffic243,761 by 2038
Trucks4%
Lanes on structure9
Traffic directionTwo-way traffic
CarriesHighway
CrossesRailroad
Detour if closed3.7 mi (6 km)
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 U.S. Highway 101 over Nwp RR / Smart built?

It was built in 1957, making it 68 years old in 2025. It was reconstructed in 1987.

What condition is U.S. Highway 101 over Nwp RR / Smart 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 March 2021.

How much traffic does U.S. Highway 101 over Nwp RR / Smart carry?

About 167,000 vehicles per day (2009 count), of which roughly 4% are trucks.

How long is U.S. Highway 101 over Nwp RR / Smart?

The structure is 136 ft (41.6 m) long with a longest span of 45 ft (13.7 m) and a deck 143 ft wide.

Who owns U.S. Highway 101 over Nwp RR / Smart?

It is owned by the State Highway Agency.