US Bridges

Main ST over Pilarcitos Creek

Poor

San Mateo County, California · 0.25 MI S/O SR 92 · Structure no. 35C0025

Built
1900
125 years old
Condition
Poor
inspected May 2023
Type
Arch - Deck
Concrete
Length
60 ft
1 main span
Daily traffic
2,350
2017 count
Owner
City
City or Municipal Highway Agency

About this bridge

Main ST over Pilarcitos Creek is a concrete arch - deck carrying Main ST over Pilarcitos Creek in San Mateo County, California. It was built in 1900, so it is 125 years old, older than the California average of 54.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 4 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

It carries about 2,350 vehicles a day, roughly 1% of them trucks, projected to reach 3,207 by 2040. The structure is 60 ft (18.3 m) long and 29 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesMain ST
CrossesPilarcitos Creek
Location0.25 MI S/O SR 92
RouteCity Street 0
CountySan Mateo County
StateCalifornia
Coordinates37.46594, -122.42885
Functional classUrban Minor Arterial

Condition and inspection

Poor

The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

ComponentRatingMeaning
Superstructure4 PoorAdvanced section loss, deterioration, spalling or scour.
Substructure4 PoorAdvanced section loss, deterioration, spalling or scour.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMay 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourUnknown foundation; not evaluated for scour
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating30 US tons
Inventory rating17.9 US tons

Structure

Structure typeArch - Deck
MaterialConcrete
DeckNot applicable
Main spans1
Design loadUnknown
Structure length60 ft (18.3 m)
Longest span60 ft (18.3 m)
Deck width29 ft (8.9 m)
Roadway width24 ft (7.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,350 (2017)
Projected traffic3,207 by 2040
Trucks1%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal Highway Agency
Historic statusListed on the National Register of Historic Places
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$927,000 (2017 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Main ST over Pilarcitos Creek built?

It was built in 1900, making it 125 years old in 2025.

What condition is Main ST over Pilarcitos Creek in?

The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in May 2023.

How much traffic does Main ST over Pilarcitos Creek carry?

About 2,350 vehicles per day (2017 count), of which roughly 1% are trucks.

How long is Main ST over Pilarcitos Creek?

The structure is 60 ft (18.3 m) long with a longest span of 60 ft (18.3 m) and a deck 29 ft wide.

Who owns Main ST over Pilarcitos Creek?

It is owned by the City or Municipal Highway Agency.