US Bridges

De Long Avenue over Ncrra (old Nwp Rr)

Good

Marin County, California · 04-MRN-101-R21.15-NVTO · Structure no. 27 0103Y

Built
1974
51 years old
Condition
Good
inspected June 2023
Type
Box Beam or Girders - Multiple
Prestressed Concrete Continuous
Length
220 ft
2 main spans
Daily traffic
30,155
2000 count
Owner
State
State Highway Agency

About this bridge

De Long Avenue over Ncrra (old Nwp Rr) is a prestressed concrete continuous box beam or girders - multiple carrying De Long Avenue over Ncrra (old Nwp Rr) in Marin County, California. It was built in 1974, so it is 51 years old, younger 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 30,155 vehicles a day, roughly 1% of them trucks, projected to reach 64,989 by 2041. The structure is 220 ft (67.1 m) long and 97 ft wide.

CarriesDe Long Avenue
CrossesNcrra (old Nwp Rr)
Location04-MRN-101-R21.15-NVTO
RouteU.S. Route 101
Coordinates38.10513, -122.56404
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 inspectionJune 2023
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 alignment8: Equal to present desirable criteria
Operating rating51.5 US tons
Inventory rating43.5 US tons

Structure

MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length220 ft (67.1 m)
Longest span134 ft (40.8 m)
Deck width97 ft (29.6 m)
Roadway width74 ft (22.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic30,155 (2000)
Projected traffic64,989 by 2041
Trucks1%
Lanes on structure5
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesRailroad
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 De Long Avenue over Ncrra (old Nwp Rr) built?

It was built in 1974, making it 51 years old in 2025.

What condition is De Long Avenue over Ncrra (old Nwp Rr) 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 June 2023.

How much traffic does De Long Avenue over Ncrra (old Nwp Rr) carry?

About 30,155 vehicles per day (2000 count), of which roughly 1% are trucks.

How long is De Long Avenue over Ncrra (old Nwp Rr)?

The structure is 220 ft (67.1 m) long with a longest span of 134 ft (40.8 m) and a deck 97 ft wide.

Who owns De Long Avenue over Ncrra (old Nwp Rr)?

It is owned by the State Highway Agency.