US Bridges

State Route 18 over Interstate 15

Fair

San Bernardino County, California · 08-SBD-018-R96.60-VCTV · Structure no. 54 0470

Built
1975
50 years old
Condition
Fair
inspected December 2024
Type
Box Beam or Girders - Single or Spread
Prestressed Concrete Continuous
Length
232 ft
2 main spans
Daily traffic
40,000
2022 count
Owner
State
State Highway Agency

About this bridge

State Route 18 over Interstate 15 is a prestressed concrete continuous box beam or girders - single or spread carrying State Route 18 over Interstate 15 in San Bernardino County, California. It was built in 1975, so it is 50 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 5 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 40,000 vehicles a day, roughly 9% of them trucks, projected to reach 55,000 by 2042. The structure is 232 ft (70.7 m) long and 88 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

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CarriesState Route 18
CrossesInterstate 15
Location08-SBD-018-R96.60-VCTV
RouteState Highway 18
CountySan Bernardino County
StateCalifornia
Coordinates34.50797, -117.32241
Functional classUrban Other Principal Arterial

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Last inspectionDecember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation3: Basically intolerable, requiring high priority of corrective action
Deck geometry7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating62.2 US tons
Inventory rating14.3 US tons

Structure

Structure typeBox Beam or Girders - Single or Spread
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length232 ft (70.7 m)
Longest span120 ft (36.6 m)
Deck width88 ft (26.8 m)
Roadway width76 ft (23.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic40,000 (2022)
Projected traffic55,000 by 2042
Trucks9%
Lanes on structure5
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesHighway
Detour if closed3.1 mi (5 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNot applicable (no waterway)

Frequently asked questions

When was State Route 18 over Interstate 15 built?

It was built in 1975, making it 50 years old in 2025.

What condition is State Route 18 over Interstate 15 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 December 2024.

How much traffic does State Route 18 over Interstate 15 carry?

About 40,000 vehicles per day (2022 count), of which roughly 9% are trucks.

How long is State Route 18 over Interstate 15?

The structure is 232 ft (70.7 m) long with a longest span of 120 ft (36.6 m) and a deck 88 ft wide.

Who owns State Route 18 over Interstate 15?

It is owned by the State Highway Agency.