US Bridges

M-68 over I-75 SB

Fair

Cheboygan County, Michigan · @ M-68 · Structure no. 000000000001507

Built
1962
63 years old
Condition
Fair
inspected April 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
142 ft
3 main spans
Daily traffic
6,551
2007 count
Owner
State
State Highway Agency

About this bridge

M-68 over I-75 SB is a steel stringer/multi-beam or girder carrying M-68 over I-75 SB in Cheboygan 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 6,551 vehicles a day, roughly 6% of them trucks, projected to reach 9,614 by 2018. The structure is 142 ft (43.3 m) long and 37 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesM-68
CrossesI-75 SB
Location@ M-68
RouteState Highway 68
CountyCheboygan County
StateMichigan
Coordinates45.40199, -84.60739
Functional classRural Minor 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.
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 inspectionApril 2023
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 geometry4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment7: Better than present minimum criteria
Operating rating62.8 US tons
Inventory rating37.8 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20 + Mod
Structure length142 ft (43.3 m)
Longest span60 ft (18.3 m)
Deck width37 ft (11.2 m)
Roadway width33 ft (10 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic6,551 (2007)
Projected traffic9,614 by 2018
Trucks6%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesHighway
Detour if closed1.2 mi (2 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 M-68 over I-75 SB built?

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

What condition is M-68 over I-75 SB 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 April 2023.

How much traffic does M-68 over I-75 SB carry?

About 6,551 vehicles per day (2007 count), of which roughly 6% are trucks.

How long is M-68 over I-75 SB?

The structure is 142 ft (43.3 m) long with a longest span of 60 ft (18.3 m) and a deck 37 ft wide.

Who owns M-68 over I-75 SB?

It is owned by the State Highway Agency.