US Bridges

SR 303L over Cap Siphons

Good

Maricopa County, Arizona · 6.4 MI W JCT I-17 · Structure no. 02915

Built
2010
15 years old
Condition
Good
inspected February 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete Continuous
Length
444 ft
3 main spans
Daily traffic
26,433
2022 count
Owner
State
State Highway Agency

About this bridge

SR 303L over Cap Siphons is a prestressed concrete continuous stringer/multi-beam or girder carrying SR 303L over Cap Siphons in Maricopa County, Arizona. It was built in 2010, so it is 15 years old, younger than the Arizona average of 47.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 8 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 26,433 vehicles a day, roughly 7% of them trucks, projected to reach 26,443 by 2042. The structure is 444 ft (135.3 m) long and 73 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesSR 303L
CrossesCap Siphons
Location6.4 MI W JCT I-17
RouteState Highway 303
CountyMaricopa County
StateArizona
Coordinates33.77626, -112.23555
Functional classUrban Principal Arterial - Other Freeway or Expressway

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck8 Very GoodNo problems noted.
Superstructure8 Very GoodNo problems noted.
Substructure8 Very GoodNo problems noted.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionFebruary 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation8: Equal to present desirable criteria
Deck geometry9: Superior to present desirable criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating89 US tons
Inventory rating36 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 25 or greater
Structure length444 ft (135.3 m)
Longest span153 ft (46.6 m)
Deck width73 ft (22.3 m)
Roadway width70 ft (21.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic26,433 (2022)
Projected traffic26,443 by 2042
Trucks7%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 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 SR 303L over Cap Siphons built?

It was built in 2010, making it 15 years old in 2025.

What condition is SR 303L over Cap Siphons in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in February 2023.

How much traffic does SR 303L over Cap Siphons carry?

About 26,433 vehicles per day (2022 count), of which roughly 7% are trucks.

How long is SR 303L over Cap Siphons?

The structure is 444 ft (135.3 m) long with a longest span of 153 ft (46.6 m) and a deck 73 ft wide.

Who owns SR 303L over Cap Siphons?

It is owned by the State Highway Agency.