US Bridges

M-48 over I-75 NB

Fair

Chippewa County, Michigan · 2.0 MI N of Mackinac Col · Structure no. 000000000001576

Built
1962
63 years old
Condition
Fair
inspected December 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
673 ft
12 main spans
Daily traffic
605
2007 count
Owner
State
State Highway Agency

About this bridge

M-48 over I-75 NB is a steel stringer/multi-beam or girder carrying M-48 over I-75 NB in Chippewa County, Michigan. It was built in 1962, so it is 63 years old, older than the Michigan average of 48.3 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 605 vehicles a day, roughly 27% of them trucks, projected to reach 476 by 2018. The structure is 673 ft (205.1 m) long and 35 ft wide. If it were closed, the detour would be 6.8 mi (11 km).

Location

Open in Google Maps
CarriesM-48
CrossesI-75 NB
Location2.0 MI N of Mackinac Col
RouteState Highway 48
CountyChippewa County
StateMichigan
Coordinates46.18714, -84.56099
Functional classRural Major 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.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionDecember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment7: Better than present minimum criteria
Operating rating79.9 US tons
Inventory rating47.8 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans12
Design loadHS 20
Structure length673 ft (205.1 m)
Longest span72 ft (21.9 m)
Deck width35 ft (10.7 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic605 (2007)
Projected traffic476 by 2018
Trucks27%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesHighway
Detour if closed6.8 mi (11 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 proposedDeck replacement with only incidental widening
Estimated improvement cost—
NavigationNot applicable (no waterway)

Frequently asked questions

When was M-48 over I-75 NB built?

It was built in 1962, making it 63 years old in 2025.

What condition is M-48 over I-75 NB 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 M-48 over I-75 NB carry?

About 605 vehicles per day (2007 count), of which roughly 27% are trucks.

How long is M-48 over I-75 NB?

The structure is 673 ft (205.1 m) long with a longest span of 72 ft (21.9 m) and a deck 35 ft wide.

Who owns M-48 over I-75 NB?

It is owned by the State Highway Agency.