US Bridges

Mariners Isl Blvd over Branch Marina Lagoon

Fair

San Mateo County, California · 0.1 MI W/O Tiller DR · Structure no. 35C0076L

Built
1999
26 years old
Condition
Fair
inspected April 2023
Type
Slab
Prestressed Concrete Continuous
Length
160 ft
3 main spans
Daily traffic
2,150
2010 count
Owner
City
City or Municipal Highway Agency

About this bridge

Mariners Isl Blvd over Branch Marina Lagoon is a prestressed concrete continuous slab carrying Mariners Isl Blvd over Branch Marina Lagoon in San Mateo County, California. It was built in 1999, so it is 26 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 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 2,150 vehicles a day, roughly 4% of them trucks, projected to reach 2,193 by 2041. The structure is 160 ft (48.8 m) long and 42 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesMariners Isl Blvd
CrossesBranch Marina Lagoon
Location0.1 MI W/O Tiller DR
RouteCity Street 0
CountySan Mateo County
StateCalifornia
Coordinates37.56261, -122.28672
Functional classUrban Minor Arterial

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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionApril 2023
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating59.6 US tons
Inventory rating35.7 US tons

Structure

Structure typeSlab
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length160 ft (48.8 m)
Longest span61 ft (18.7 m)
Deck width42 ft (12.7 m)
Roadway width34 ft (10.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,150 (2010)
Projected traffic2,193 by 2041
Trucks4%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed3.7 mi (6 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal Highway Agency
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 Mariners Isl Blvd over Branch Marina Lagoon built?

It was built in 1999, making it 26 years old in 2025.

What condition is Mariners Isl Blvd over Branch Marina Lagoon 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 April 2023.

How much traffic does Mariners Isl Blvd over Branch Marina Lagoon carry?

About 2,150 vehicles per day (2010 count), of which roughly 4% are trucks.

How long is Mariners Isl Blvd over Branch Marina Lagoon?

The structure is 160 ft (48.8 m) long with a longest span of 61 ft (18.7 m) and a deck 42 ft wide.

Who owns Mariners Isl Blvd over Branch Marina Lagoon?

It is owned by the City or Municipal Highway Agency.