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)

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.

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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.