US Bridges

M-55 WB over I-75 NB

Fair

Roscommon County, Michigan · 0.4 MI N of Maple Valley · Structure no. 000000000009022

Built
1971
54 years old
Condition
Fair
inspected August 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
441 ft
5 main spans
Daily traffic
7,828
2023 count
Owner
State
State Highway Agency

About this bridge

M-55 WB over I-75 NB is a steel stringer/multi-beam or girder carrying M-55 WB over I-75 NB in Roscommon County, Michigan. It was built in 1971, so it is 54 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 7,828 vehicles a day, roughly 8% of them trucks, projected to reach 8,650 by 2043. The structure is 441 ft (134.4 m) long and 44 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesM-55 WB
CrossesI-75 NB
Location0.4 MI N of Maple Valley
RouteInterstate 75
CountyRoscommon County
StateMichigan
Coordinates44.31427, -84.50448
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.
Last inspectionAugust 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating87.9 US tons
Inventory rating52.5 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans5
Design loadHS 20
Structure length441 ft (134.4 m)
Longest span122 ft (37.1 m)
Deck width44 ft (13.5 m)
Roadway width40 ft (12.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic7,828 (2023)
Projected traffic8,650 by 2043
Trucks8%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
Detour if closed1.2 mi (2 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 M-55 WB over I-75 NB built?

It was built in 1971, making it 54 years old in 2025.

What condition is M-55 WB 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 August 2023.

How much traffic does M-55 WB over I-75 NB carry?

About 7,828 vehicles per day (2023 count), of which roughly 8% are trucks.

How long is M-55 WB over I-75 NB?

The structure is 441 ft (134.4 m) long with a longest span of 122 ft (37.1 m) and a deck 44 ft wide.

Who owns M-55 WB over I-75 NB?

It is owned by the State Highway Agency.