San Mateo County, CA

393 public highway bridges

San Mateo County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, San Mateo County, California contains 393 public highway bridges. Roughly 16.3% are rated “Good,” 31.3% “Fair,” and 5.3% “Poor.” Poor means the lowest applicable deck, superstructure, substructure, or culvert rating is 4 or below on the 0–9 NBI scale. It is a condition category, not a live safety or closure decision.

Responsible agencies inspect covered bridges on risk-based intervals under current NBIS rules and submit inventory data to FHWA annually. The list below shows every NBI-tracked bridge in the county. Use the “Sort by” controls to change the ordering, and click any row for its reported inspection date, traffic count, and condition fields.

Source: FHWA National Bridge Inventory. See methodology for full definitions.

393
Total Bridges
16.3%
Good
31.3%
Fair
5.3%
Poor Condition

Condition Distribution

Good
16.3% (64)
Fair
31.3% (123)
Poor
5.3% (21)

All Bridges (393)

US 101, MCDONNELL

Fair

Over: MILLBRAE SLOUGH

04-SM-101-18.09-MLBR, San Mateo, CA

Built 1947 Load: 32.4 t ADT: 226,000

SAN BRUNO AVENUE

Fair

Over: SAN BRUNO CANAL

04-SM-101-R20.39, San Mateo, CA

Built 1947 Load: 32.4 t ADT: 10,100

N101-SIERRA PT OFF

Fair

Over: CALTRAIN & UP RR

04-SM-101-23.66-BSBN, San Mateo, CA

Built 1982 Load: 32.4 t ADT: 1,100

U.S. HIGHWAY 101

Fair

Over: BOREL CREEK

04-SM-101-11.67-SM, San Mateo, CA

Built 1954 Load: 32.4 t ADT: 195,000

STATE ROUTE 92

Fair

Over: FOSTER CITY LAGOON

04-SM-092-R13.83-FSTC, San Mateo, CA

Built 1967 Load: 32.4 t ADT: 86,000

N35-N1 CNNCTR RMP

Fair

Over: LAKESHIRE DRIVE

04-SM-035-R28.64-DLC, San Mateo, CA

Built 1972 Load: 32.4 t ADT: 7,300

STATE ROUTE 280 SB

Fair

Over: TROUSDALE DRIVE

04-SM-280-R17.16, San Mateo, CA

Built 1969 Load: 32.4 t ADT: 54,500

STATE ROUTE 280 NB

Fair

Over: TROUSDALE DRIVE

04-SM-280-R17.16, San Mateo, CA

Built 1969 Load: 32.4 t ADT: 54,500

INTERSTATE 280 SB

Fair

Over: RANCHO PULGAS VISTA ROAD

04-SM-280-9.41, San Mateo, CA

Built 1973 Load: 32.4 t ADT: 51,500

INTERSTATE 280 NB

Fair

Over: RANCHO PULGAS VISTA ROAD

04-SM-280-9.41, San Mateo, CA

Built 1973 Load: 32.4 t ADT: 55,500

INTERSTATE 280 SB

Fair

Over: SERVICE ROAD

04-SM-280-R6.99, San Mateo, CA

Built 1973 Load: 32.4 t ADT: 50,000

INTERSTATE 280 NB

Fair

Over: SERVICE ROAD

04-SM-280-R6.99, San Mateo, CA

Built 1973 Load: 32.4 t ADT: 50,000

STATE ROUTE 1

Fair

Over: DENNISTON CREEK

04-SM-001-33.30-HMBY, San Mateo, CA

Built 1990 Load: 32.4 t ADT: 15,600

OYSTER POINT-N101

Fair

Over: OYSTER POINT DRAIN CLVRT

04-SM-101-22.89-SSF, San Mateo, CA

Built 1995 Load: 32.4 t ADT: 8,000

BRADFORD ST

Fair

Over: REDWOOD CREEK

BTWN MAIN ST & JEFFSN AVE, San Mateo, CA

Built 1966 Load: 32.4 t ADT: 2,000

MAIN ST

Fair

Over: REDWOOD CREEK

@ VETERANS BLVD, San Mateo, CA

Built 1989 Load: 32.4 t ADT: 9,000

VETERANS BLVD

Fair

Over: REDWOOD CREEK

EAST OF MAIN ST, San Mateo, CA

Built 1990 Load: 32.4 t ADT: 26,000

CRYSTAL SPRINGS RD

Fair

Over: SAN MATEO CREEK

POLHEMUS ROAD, San Mateo, CA

Built 1974 Load: 32.4 t ADT: 1,637

MARINERS ISL BLVD

Fair

Over: BRANCH MARINA LAGOON

0.1 MI W/O TILLER DR, San Mateo, CA

Built 1999 Load: 32.4 t ADT: 2,150

CHESTNUT AVE

Fair

Over: COLMA CANAL

0.1 MI S COMMERCIAL AVE, San Mateo, CA

Built 1976 Load: 32.4 t ADT: 23,265

ROAD-1 SOUTH

Fair

Over: EAST UNDERCROSSING

EAST OF US 101, San Mateo, CA

Built 1973 Load: 32.4 t ADT: 64,200

ROAD-1 NORTH

Fair

Over: R-1N OFF-RAMP

EAST OF US 101, San Mateo, CA

Built 1973 Load: 32.4 t ADT: 19,170

ROAD-1 SOUTH

Fair

Over: R-1S OFF-RAMP

EAST OF US 101, San Mateo, CA

Built 1973 Load: 32.4 t ADT: 19,170

THIRD AVENUE

Fair

Over: SEAL SLOUGH

0.4 MI W MRNRS ISLAND BL, San Mateo, CA

Built 1985 Load: 32.4 t ADT: 11,290

SAN PEDRO AVE

Fair

Over: SAN PEDRO CREEK

PACIFICA, San Mateo, CA

Built 1996 Load: 32.4 t ADT: 4,500

ANZA BLVD

Fair

Over: BURLINGAME LAGOON

EAST OF SH 101, San Mateo, CA

Built 1989 Load: 32.4 t ADT: 10,000

WESTRIDGE DR

Fair

Over: CORTE MADERA CREEK

0.4 MI N/E PORTOLA RD, San Mateo, CA

Built 1990 Load: 32.4 t ADT: 1,465

4TH AVENUE

Fair

Over: SAN MATEO CREEK

4TH AVE @ SR 101, San Mateo, CA

Built 1998 Load: 32.4 t ADT: 7,500

SF AIRPORT-S101 ON

Fair

Over: AIRPORT PROPERTY

A1 - B7 OF 35 0274K, San Mateo, CA

Built 1987 Load: 32.4 t ADT: 10,270

NORFOLK STREET

Fair

Over: SAN MATEO CREEK

SOUTH OF 3RD AVE, San Mateo, CA

Built 2001 Load: 32.4 t ADT: 14,780

ENTRADA WAY

Fair

Over: LA HONDA CREEK

0.1 MI. EAST OF SR 84, San Mateo, CA

Built 1973 Load: 32.4 t ADT: 100

FOX HOLLOW ROAD

Fair

Over: BEAR GULCH CREEK

500 FT S. OF SR 84, San Mateo, CA

Built 1975 Load: 32.4 t ADT: 50

ISLAND PARKWAY

Fair

Over: AUTOBAHN MOTORS

0.1 M. N. OF MARINE PKWY, San Mateo, CA

Built 2004 Load: 32.4 t ADT: 2,500

INTERSTATE 280

Fair

Over: STANFORD LINEAR ACCEL

04-SM-280-R1.02, San Mateo, CA

Built 1965 Load: 33.0 t ADT: 101,000

INTERSTATE 280

Fair

Over: SAN MATEO CR,CRYSTAL SPR

04-SM-280-R12.73, San Mateo, CA

Built 1967 Load: 33.4 t ADT: 106,000

SNEATH LN

Fair

Over: HILLSIDE

E CLAREMONT DR, San Mateo, CA

Built 1975 Load: 34.3 t ADT: 13,000

SNEATH LN

Fair

Over: HILLSIDE

EAST CLAREMONT DR, San Mateo, CA

Built 1975 Load: 34.3 t ADT: 13,000

STATE ROUTE 92

Fair

Over: PILARCITOS CREEK

04-SM-092-3.30, San Mateo, CA

Built 1965 Load: 35.3 t ADT: 23,300

MIRAMONTES ST

Fair

Over: ARROYO LEON CREEK

0.3 MI E OF MAIN ST, San Mateo, CA

Built 1986 Load: 37.3 t ADT: 310

U.S. HIGHWAY 101

Fair

Over: CALTRAIN,UP RR,SIERRA PT

04-SM-101-23.66-BSBN, San Mateo, CA

Built 1956 Load: 37.9 t ADT: 196,000

SAN MATEO AVE

Fair

Over: COLMA CREEK

.1 MI W/O AIRPORT BLVD, San Mateo, CA

Built 1960 Load: 38.2 t ADT: 9,343

ALPINE RD

Fair

Over: SAN FRANCISQUITO CREEK

0.3 MI N OF I-280, San Mateo, CA

Built 1950 Load: 39.2 t ADT: 16,957

PRODUCE AVE

Fair

Over: COLMA CREEK

S/O SAN MATEO AVE, San Mateo, CA

Built 1977 Load: 40.8 t ADT: 22,510

FOSTER CITY BLVD

Fair

Over: FOSTER CITY LAGOON

EAST OF BOUNTY DR, San Mateo, CA

Built 1966 Load: 40.8 t ADT: 5,042

FOSTER CITY BLVD

Fair

Over: FOSTER CITY LAGOON

EAST OF BOUNTY DRIVE, San Mateo, CA

Built 1966 Load: 40.8 t ADT: 5,005

SHELL BLVD

Fair

Over: FOSTER CITY LAGOON

.3 MI N/O BEACH PARK ROAD, San Mateo, CA

Built 1966 Load: 40.8 t ADT: 2,103

SHELL BLVD

Fair

Over: FOSTER CITY LAGOON

.3 MI N/O BEACH PARK ROAD, San Mateo, CA

Built 1966 Load: 40.8 t ADT: 2,126

STAGE ROAD

Fair

Over: PESCADERO CREEK

SOUTH OF NORTH ST, San Mateo, CA

Built 1961 Load: 42.1 t ADT: 1,230

I-280 NB OFFRAMP

Fair

Over: LOS TRANCOS CREEK

04-SM-280-R0.01, San Mateo, CA

Built 1969 Load: 45.7 t ADT: 6,700

U.S. HIGHWAY 101

Fair

Over: UP RR SPUR

04-SM-101-5.50-RDWC, San Mateo, CA

Built 1958 Load: 46.0 t ADT: 195,000

Read our methodology - how this data is sourced, computed, and verified.

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Data sourced from official public datasets. See our methodology for details. Retrieved and formatted by PlainBridges

Every figure on PlainBridge is rendered directly from federal source data, no number is typed in by an editor. This page draws directly on federal source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.