San Mateo County, CA

393 public highway bridges

San Mateo County Bridge Snapshot

San Mateo County, California contains 393 public highway bridges in the FHWA National Bridge Inventory. Roughly 16.3% are rated “Good,” 31.3% “Fair,” 5.3% “Poor,” and 5.3% are classified as structurally deficient — the federal designation for spans whose deck, superstructure, or substructure has been rated 4 or below on the 0–9 NBI scale. Structurally deficient does not mean unsafe to cross; it means the bridge is on the priority list for repair or replacement.

Inspections in CA are conducted by certified engineers from the state Department of Transportation on a 24-month cycle, and results are reported back to the FHWA each spring. The list below shows every NBI-tracked bridge in the county, sorted by inventory load rating. Use the “Sort by” controls to surface the lowest-rated spans first, and click any row for full inspection history, traffic counts, and condition trends.

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

393
Total Bridges
16.3%
Good
5.3%
Poor
5.3%
Structurally Deficient

Condition Distribution

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

Related

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Data sourced from official U.S. government datasets. See our methodology for details. Retrieved and formatted by PlainBridges Editorial