US Bridges

SR 77; Miracle Mil over I 10

Fair

Pima County, Arizona · JCT SR 77 · Structure no. 02362

Built
1995
30 years old
Condition
Fair
inspected December 2024
Type
Box Beam or Girders - Single or Spread
Prestressed Concrete Continuous
Length
256 ft
2 main spans
Daily traffic
34,300
2022 count
Owner
State
State Highway Agency

About this bridge

SR 77; Miracle Mil over I 10 is a prestressed concrete continuous box beam or girders - single or spread carrying SR 77; Miracle Mil over I 10 in Pima County, Arizona. It was built in 1995, so it is 30 years old, younger than the Arizona average of 47.8 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.

It carries about 34,300 vehicles a day, roughly 9% of them trucks, projected to reach 34,310 by 2042. The structure is 256 ft (78 m) long and 92 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesSR 77; Miracle Mil
CrossesI 10
LocationJCT SR 77
RouteState Highway 77
CountyPima County
StateArizona
Coordinates32.2601, -111.003
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Last inspectionDecember 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 rating88 US tons
Inventory rating39 US tons

Structure

Structure typeBox Beam or Girders - Single or Spread
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length256 ft (78 m)
Longest span125 ft (38.1 m)
Deck width92 ft (28 m)
Roadway width72 ft (21.9 m)
Vertical clearance over deck20 ft (6.1 m)

Traffic and service

Average daily traffic34,300 (2022)
Projected traffic34,310 by 2042
Trucks9%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesHighway
Detour if closed1.9 mi (3 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 77; Miracle Mil over I 10 built?

It was built in 1995, making it 30 years old in 2025.

What condition is SR 77; Miracle Mil over I 10 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 SR 77; Miracle Mil over I 10 carry?

About 34,300 vehicles per day (2022 count), of which roughly 9% are trucks.

How long is SR 77; Miracle Mil over I 10?

The structure is 256 ft (78 m) long with a longest span of 125 ft (38.1 m) and a deck 92 ft wide.

Who owns SR 77; Miracle Mil over I 10?

It is owned by the State Highway Agency.