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)

STATE ROUTE 114

Unknown

Over: U.S. HWY 101, RAMPS

04-SM-114-5.00-EAPA, San Mateo, CA

Built 2019 ADT: 207,900

PEDESTRIAN WALKWAY

Unknown

Over: STATE ROUTE 1

04-SM-001-R44.07-PFA, San Mateo, CA

Built 2019 ADT: 32,500

BAYFRONT POC

Unknown

Over: STATE ROUTE 84

04-SM-084-R27.02-MLP, San Mateo, CA

Built 2022 ADT: 27,500

CALTRAIN & UP RR

Unknown

Over: AIRPORT BLVD

0.1 MI N SAN MATEO AVE, San Mateo, CA

Built 1927 ADT: 25,127

DUNMAN ST

Unknown

Over: HICKEY BLVD

OVER HICKEY BLVD, San Mateo, CA

Built 1965 ADT: 23,578

PEDESTRIAN WALKWAY

Unknown

Over: JUNIPERO SERRA BL

0.2 MI S/O HICKEY RD, San Mateo, CA

Built 1968 ADT: 10,000

PACIFIC BLVD

Unknown

Over: HILLSDALE BLVD

PACIFIC BLVD @ HILLSDALE, San Mateo, CA

Built 1965 ADT: 25,620

CALTRAIN & UP RR

Unknown

Over: HILLSDALE BLVD

CALTRAIN @ HILLSDALE BLVD, San Mateo, CA

Built 1965 ADT: 25,620

PEDESTRIAN WALKWAY

Unknown

Over: N MCDONNELL ROAD

NORHT OF SAN BRUNO AVE, San Mateo, CA

Built 1986 ADT: 27,000

CALTRAIN & UP RR

Unknown

Over: TILTON AVENUE

EAST OF RAILROAD AVE, San Mateo, CA

Built 1903 ADT: 4,900

CITY PARKING LOT

Unknown

Over: SM DR AND ELLSWORTH AVE

SOUTH OF 3RD AVE, San Mateo, CA

Built 1966 ADT: 6,580

CALTRAIN & UP RR

Unknown

Over: SANTA INEZ AVE

EAST OF RAMONA ST, San Mateo, CA

Built 1903 ADT: 1,270

CALTRAIN & UP RR

Unknown

Over: EAST POPLAR AVE

EAST RAMONA ST, San Mateo, CA

Built 1903 ADT: 9,270

TUNNEL AVE

Unknown

Over: UP RR

TUNNEL AVE @ UPRR, San Mateo, CA

Built 2007 ADT: 20

DEPARTING FLT TRFC

Unknown

Over: ARRIVING FLIGHT TRAFFIC

EAST OF US RT 101, San Mateo, CA

Built 1973 ADT: 4,890

ROAD-1 NORTH

Unknown

Over: MCDONNELL RD

EAST OF SH 101, San Mateo, CA

Built 1970 ADT: 4,490

ROAD-1 SOUTH

Unknown

Over: MCDONNELL RD

EAST OF SH 101, San Mateo, CA

Built 1970 ADT: 4,490

R-1S

Unknown

Over: R-1S

EAST OF US 101, San Mateo, CA

Built 1973 ADT: 12,930

PEDESTRIAN WALKWAY

Unknown

Over: 31ST AVE

WEST OF SH 82, San Mateo, CA

Built 1983 ADT: 3,000

CALTRAIN & UP RR

Unknown

Over: 42ND AVE

EAST OF US 101, San Mateo, CA

Built 1989 ADT: 7,060

OYSTER POINT BLVD

Unknown

Over: CALTRAIN & UP RR

0.1 MILES W OF GATEWAY BL, San Mateo, CA

Built 1994 ADT: 385

AIRPORT TERM OFF-R

Unknown

Over: US 101

H16 TO A26 OF 35 0275K, San Mateo, CA

Built 1987 ADT: 5,000

AIRPORT TERM ON-RP

Unknown

Over: US 101

RAMP TO RTE SB 101, San Mateo, CA

Built 1996 ADT: 4,890

I380 NB ON-RAMP

Unknown

Over: US 101

SPAN 9 HINGE TO BENT 19, San Mateo, CA

Built 1996 ADT: 4,890

S101-SFO INTERNTNL

Unknown

Over: NB101-SFO DOMESTIC TRMNL

SIU H19 & NIU HP TO B22, San Mateo, CA

Built 1996 ADT: 4,890

AIRPORT TERM OFF-R

Unknown

Over: US 101

RAMP FROM RTE SB 101, San Mateo, CA

Built 1996 ADT: 7,154

GARAGE CONNECTOR

Unknown

Over: NORTH/SOUTH GARAGE

0.3 MI E/O N. MACDONNELL, San Mateo, CA

Built 2000 ADT: 2,500

INTERNATIONAL VIA

Unknown

Over: AIRPORT ACCESS ROAD

EAST OF MCDONNELL ROAD, San Mateo, CA

Built 2001 ADT: 18,000

INTNL RETURN LOOP

Unknown

Over: AIRPORT ACCS RDS,N MCDON

AT N.MCDONNELL RD, San Mateo, CA

Built 2001 ADT: 50,000

PEDESTRIAN WALKWAY

Unknown

Over: UPPER LEVEL DOMESTIC VIA

TERMINAL 1 - AREA B, San Mateo, CA

Built 2006 ADT: 19,170

PEDESTRIAN WALKWAY

Unknown

Over: UPPER LEVEL DOMESTIC VIA

TERMINAL 2 - AREA D, San Mateo, CA

Built 2006 ADT: 19,170

PEDESTRIAN WALKWAY

Unknown

Over: UPPER LEVEL DOMESTIC VIA

TERMINAL 3 - AREA F, San Mateo, CA

Built 2006 ADT: 19,170

AIR TRAIN TRACKS

Unknown

Over: UPPER LEVEL DOMESTIC VIA

SF AIRPORT DOMESTIC TERM, San Mateo, CA

Built 2003 ADT: 19,170

AIR TRAIN TRACKS

Unknown

Over: BART, INTERNL VIA, RAMPS

SF AIR INTERNATIONAL TERM, San Mateo, CA

Built 2003 ADT: 19,170

AIR TRAIN TRACKS

Unknown

Over: NORTH MCDONNELL RD, NB

0.2 MI S OF SAN BRUNO AVE, San Mateo, CA

Built 2003 ADT: 5,000

PORTOLA RD

Fair

Over: ALEMBIQUE CREEK

0.25 MI E OF SH 84, San Mateo, CA

Built 1914 Load: 14.3 t ADT: 2,969

CRYSTAL SPRINGS RD

Fair

Over: SAN MATEO CREEK

0.24 MI W OF SH 82, San Mateo, CA

Built 1901 Load: 14.9 t ADT: 3,630

MADERA LANE

Fair

Over: EL CORTE DE MADERA CRK

0.1 MI N OF SH 84, San Mateo, CA

Built 1920 Load: 14.9 t ADT: 16

CRYSTAL SPRINGS RD

Fair

Over: SAN MATEO CREEK

0.4 MI N TARTAN TRAILS RD, San Mateo, CA

Built 1904 Load: 15.2 t ADT: 10,000

STATE ROUTE 82

Fair

Over: CORDILLERAS CREEK

04-SM-082-5.15-RDWC, San Mateo, CA

Built 1915 Load: 15.6 t ADT: 25,000

BERNAL AVE

Fair

Over: EASTON CREEK

EAST OF EASTON DR, San Mateo, CA

Built 1936 Load: 15.6 t ADT: 300

ALPINE ROAD

Fair

Over: ALPINE CREEK

0.01 MI W OF PESCADERO RD, San Mateo, CA

Built 1920 Load: 15.6 t ADT: 91

MOUNTAIN HOME RD

Fair

Over: BEAR CREEK

0.3 MI S OF S.H. 84, San Mateo, CA

Built 1900 Load: 15.6 t ADT: 500

RAILROAD AVE

Fair

Over: SAN MATEO CREEK

SOUTH OF TILTON, San Mateo, CA

Built 1902 Load: 15.6 t ADT: 230

GAZOS CREEK ROAD

Fair

Over: HILLSIDE

0.8 MI E/O CLOVERDALE RD, San Mateo, CA

Built 1983 Load: 15.6 t ADT: 75

SEASIDE SCH RD SHV

Fair

Over: HILLSIDE

0.25 MILES W/O STAGE RD, San Mateo, CA

Built 1976 Load: 15.6 t ADT: 25

STATE ROUTE 84

Fair

Over: WEST UNION CREEK

04-SM-084-19.89-WDS, San Mateo, CA

Built 1903 Load: 16.2 t ADT: 6,600

STATE ROUTE 82

Fair

Over: BELMONT CREEK

04-SM-082-7.36-SM, San Mateo, CA

Built 1941 Load: 16.2 t ADT: 34,750

BEAN HOLLOW ROAD

Fair

Over: ARROYO DE LOS FRIJOLES

0.2 MI NORTH OF S.H. 1, San Mateo, CA

Built 1922 Load: 16.2 t ADT: 175

INDUSTRIAL BLVD

Fair

Over: CORDILLERAS CREEK

NORTH OF 'G' ST, San Mateo, CA

Built 1930 Load: 16.2 t ADT: 8,612

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