US Bridges

M-72 over S Br Au Sable River

Fair

Crawford County, Michigan · 4.4 MI W of Oscoda Col · Structure no. 000000000002054

Built
1958
67 years old
Condition
Fair
inspected June 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
224 ft
3 main spans
Daily traffic
2,140
2015 count
Owner
State
State Highway Agency

About this bridge

M-72 over S Br Au Sable River is a steel stringer/multi-beam or girder carrying M-72 over S Br Au Sable River in Crawford County, Michigan. It was built in 1958, so it is 67 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 2,140 vehicles a day, roughly 10% of them trucks, projected to reach 2,480 by 2035. The structure is 224 ft (68.2 m) long and 37 ft wide. If it were closed, the detour would be 19.3 mi (31 km).

Location

Open in Google Maps
CarriesM-72
CrossesS Br Au Sable River
Location4.4 MI W of Oscoda Col
RouteState Highway 72
CountyCrawford County
StateMichigan
Coordinates44.61426, -84.45612
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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJune 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating68.6 US tons
Inventory rating41.1 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length224 ft (68.2 m)
Longest span81 ft (24.7 m)
Deck width37 ft (11.3 m)
Roadway width34 ft (10.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,140 (2015)
Projected traffic2,480 by 2035
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed19.3 mi (31 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—
NavigationNo navigation control on waterway

Frequently asked questions

When was M-72 over S Br Au Sable River built?

It was built in 1958, making it 67 years old in 2025.

What condition is M-72 over S Br Au Sable River 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 June 2023.

How much traffic does M-72 over S Br Au Sable River carry?

About 2,140 vehicles per day (2015 count), of which roughly 10% are trucks.

How long is M-72 over S Br Au Sable River?

The structure is 224 ft (68.2 m) long with a longest span of 81 ft (24.7 m) and a deck 37 ft wide.

Who owns M-72 over S Br Au Sable River?

It is owned by the State Highway Agency.