US Bridges

Lapeer RD (M-21) over Cowhey CR

Fair

St. Clair County, Michigan · 1.3 MI E of M-19 · Structure no. 000000000009918

Built
1953
72 years old, rebuilt 2002
Condition
Fair
inspected March 2023
Type
Box Beam or Girders - Single or Spread
Prestressed Concrete
Length
35 ft
1 main span
Daily traffic
2,514
2023 count
Owner
County
County Highway Agency

About this bridge

Lapeer RD (M-21) over Cowhey CR is a prestressed concrete box beam or girders - single or spread carrying Lapeer RD (M-21) over Cowhey CR in St. Clair County, Michigan. It was built in 1953 and reconstructed in 2002, so it is 72 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 6 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 2,514 vehicles a day, roughly 10% of them trucks, projected to reach 3,063 by 2043. The structure is 35 ft (10.7 m) long and 47 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

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CarriesLapeer RD (M-21)
CrossesCowhey CR
Location1.3 MI E of M-19
RouteCounty Highway 0
CountySt. Clair County
StateMichigan
Coordinates42.99433, -82.73917
Functional classRural Major Collector

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.
Superstructure8 Very GoodNo problems noted.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMarch 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating107.1 US tons
Inventory rating64.3 US tons

Structure

Structure typeBox Beam or Girders - Single or Spread
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length35 ft (10.7 m)
Longest span32 ft (9.7 m)
Deck width47 ft (14.2 m)
Roadway width43 ft (13.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,514 (2023)
Projected traffic3,063 by 2043
Trucks10%
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

OwnerCounty Highway Agency
Maintained byCounty 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 Lapeer RD (M-21) over Cowhey CR built?

It was built in 1953, making it 72 years old in 2025. It was reconstructed in 2002.

What condition is Lapeer RD (M-21) over Cowhey CR 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 March 2023.

How much traffic does Lapeer RD (M-21) over Cowhey CR carry?

About 2,514 vehicles per day (2023 count), of which roughly 10% are trucks.

How long is Lapeer RD (M-21) over Cowhey CR?

The structure is 35 ft (10.7 m) long with a longest span of 32 ft (9.7 m) and a deck 47 ft wide.

Who owns Lapeer RD (M-21) over Cowhey CR?

It is owned by the County Highway Agency.