US Bridges

M-99 M-50 over Mill Race

Fair

Eaton County, Michigan · S of State ST · Structure no. 000000000002299

Built
1995
30 years old
Condition
Fair
inspected May 2023
Type
Box Beam or Girders - Single or Spread
Prestressed Concrete
Length
38 ft
1 main span
Daily traffic
15,977
2007 count
Owner
State
State Highway Agency

About this bridge

M-99 M-50 over Mill Race is a prestressed concrete box beam or girders - single or spread carrying M-99 M-50 over Mill Race in Eaton County, Michigan. It was built in 1995, so it is 30 years old, younger 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 15,977 vehicles a day, roughly 5% of them trucks, projected to reach 21,679 by 2018. The structure is 38 ft (11.6 m) long and 93 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesM-99 M-50
CrossesMill Race
LocationS of State ST
RouteState Highway 99
CountyEaton County
StateMichigan
Coordinates42.50903, -84.65596
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
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMay 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry6: Equal to present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating63.9 US tons
Inventory rating36.4 US tons

Structure

Structure typeBox Beam or Girders - Single or Spread
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 25 or greater
Structure length38 ft (11.6 m)
Longest span36 ft (11.1 m)
Deck width93 ft (28.4 m)
Roadway width62 ft (19 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic15,977 (2007)
Projected traffic21,679 by 2018
Trucks5%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed3.7 mi (6 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-99 M-50 over Mill Race built?

It was built in 1995, making it 30 years old in 2025.

What condition is M-99 M-50 over Mill Race 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 May 2023.

How much traffic does M-99 M-50 over Mill Race carry?

About 15,977 vehicles per day (2007 count), of which roughly 5% are trucks.

How long is M-99 M-50 over Mill Race?

The structure is 38 ft (11.6 m) long with a longest span of 36 ft (11.1 m) and a deck 93 ft wide.

Who owns M-99 M-50 over Mill Race?

It is owned by the State Highway Agency.