US Bridges

M-50 over Little Thornapple River

Good

Eaton County, Michigan · 6.4 MI NW of Charlotte · Structure no. 000000000002229

Built
2013
12 years old
Condition
Good
inspected March 2025
Type
Box Beam or Girders - Multiple
Prestressed Concrete
Length
88 ft
1 main span
Daily traffic
2,842
2013 count
Owner
State
State Highway Agency

About this bridge

M-50 over Little Thornapple River is a prestressed concrete box beam or girders - multiple carrying M-50 over Little Thornapple River in Eaton County, Michigan. It was built in 2013, so it is 12 years old, younger than the Michigan average of 48.3 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 2,842 vehicles a day, roughly 17% of them trucks, projected to reach 3,350 by 2032. The structure is 88 ft (26.8 m) long and 47 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

CarriesM-50
CrossesLittle Thornapple River
Location6.4 MI NW of Charlotte
RouteState Highway 50
Coordinates42.63845, -84.88203
Functional classRural Minor Arterial

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMarch 2025
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry7: Better than present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating64.6 US tons
Inventory rating47.5 US tons

Structure

MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadGreater than HL 93
Structure length88 ft (26.8 m)
Longest span87 ft (26.6 m)
Deck width47 ft (14.4 m)
Roadway width44 ft (13.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,842 (2013)
Projected traffic3,350 by 2032
Trucks17%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.1 mi (5 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-50 over Little Thornapple River built?

It was built in 2013, making it 12 years old in 2025.

What condition is M-50 over Little Thornapple River in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in March 2025.

How much traffic does M-50 over Little Thornapple River carry?

About 2,842 vehicles per day (2013 count), of which roughly 17% are trucks.

How long is M-50 over Little Thornapple River?

The structure is 88 ft (26.8 m) long with a longest span of 87 ft (26.6 m) and a deck 47 ft wide.

Who owns M-50 over Little Thornapple River?

It is owned by the State Highway Agency.