US Bridges

Explorer Road over Arroyo Seco

FairPosted for load

Los Angeles County, California · 2.4KM N. of I-210/ARROYO · Structure no. JPLFACILITY0285

Built
1971
54 years old
Condition
Fair
inspected May 2024
Type
Box Beam or Girders - Multiple
Concrete Continuous
Length
160 ft
2 main spans
Daily traffic
3,492
2017 count
Owner
Federal
NASA

About this bridge

Explorer Road over Arroyo Seco is a concrete continuous box beam or girders - multiple carrying Explorer Road over Arroyo Seco in Los Angeles County, California. It was built in 1971, so it is 54 years old, younger than the California average of 54.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. Its operating status is: posted for load restriction.

It carries about 3,492 vehicles a day, roughly 5% of them trucks, projected to reach 4,411 by 2035. The structure is 160 ft (48.8 m) long and 31 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

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CarriesExplorer Road
CrossesArroyo Seco
Location2.4KM N. of I-210/ARROYO
RouteCity Street 0
CountyLos Angeles County
StateCalifornia
Coordinates34.20297, -118.16649
Functional classUrban Collector

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionMay 2024
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation7: Better than present minimum criteria
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment3: Basically intolerable, requiring high priority of corrective action
Operating rating65.8 US tons
Inventory rating43.8 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length160 ft (48.8 m)
Longest span80 ft (24.4 m)
Deck width31 ft (9.4 m)
Roadway width22 ft (6.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,492 (2017)
Projected traffic4,411 by 2035
Trucks5%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed3.7 mi (6 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerNASA
Maintained byNASA
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost$19,000 (2024 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Explorer Road over Arroyo Seco built?

It was built in 1971, making it 54 years old in 2025.

What condition is Explorer Road over Arroyo Seco in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in May 2024.

How much traffic does Explorer Road over Arroyo Seco carry?

About 3,492 vehicles per day (2017 count), of which roughly 5% are trucks.

How long is Explorer Road over Arroyo Seco?

The structure is 160 ft (48.8 m) long with a longest span of 80 ft (24.4 m) and a deck 31 ft wide.

Who owns Explorer Road over Arroyo Seco?

It is owned by the NASA.