US Bridges

12th ST over I-10

Good

Maricopa County, Arizona · 3.1 MI E JCT I-17 · Structure no. 01970

Built
1986
39 years old
Condition
Good
inspected May 2024
Type
Box Beam or Girders - Single or Spread
Prestressed Concrete Continuous
Length
336 ft
2 main spans
Daily traffic
4,277
2024 count
Owner
State
State Highway Agency

About this bridge

12th ST over I-10 is a prestressed concrete continuous box beam or girders - single or spread carrying 12th ST over I-10 in Maricopa County, Arizona. It was built in 1986, so it is 39 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 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 4,277 vehicles a day, roughly 2% of them trucks, projected to reach 4,287 by 2042. The structure is 336 ft (102.4 m) long and 71 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

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Carries12th ST
CrossesI-10
Location3.1 MI E JCT I-17
RouteCity Street 0
CountyMaricopa County
StateArizona
Coordinates33.4614, -112.0564
Functional classUrban Collector

Condition and inspection

Good

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

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Last inspectionMay 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation7: Better than present minimum criteria
Deck geometry9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating81 US tons
Inventory rating49.1 US tons

Structure

Structure typeBox Beam or Girders - Single or Spread
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length336 ft (102.4 m)
Longest span165 ft (50.3 m)
Deck width71 ft (21.6 m)
Roadway width54 ft (16.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic4,277 (2024)
Projected traffic4,287 by 2042
Trucks2%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesHighway
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemNo

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 12th ST over I-10 built?

It was built in 1986, making it 39 years old in 2025.

What condition is 12th ST over I-10 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 May 2024.

How much traffic does 12th ST over I-10 carry?

About 4,277 vehicles per day (2024 count), of which roughly 2% are trucks.

How long is 12th ST over I-10?

The structure is 336 ft (102.4 m) long with a longest span of 165 ft (50.3 m) and a deck 71 ft wide.

Who owns 12th ST over I-10?

It is owned by the State Highway Agency.