US Bridges

County RD 478 over Black River

Good

Marquette County, Michigan · 3 Miles N E of Republic · Structure no. 000000000006543

Built
2019
6 years old
Condition
Good
inspected October 2023
Type
Culvert
Concrete
Length
47 ft
1 main span
Daily traffic
44
2019 count
Owner
County
County Highway Agency

About this bridge

County RD 478 over Black River is a concrete culvert carrying County RD 478 over Black River in Marquette County, Michigan. It was built in 2019, so it is 6 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 8 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 44 vehicles a day, roughly 4% of them trucks, projected to reach 68 by 2039. The structure is 47 ft (14.3 m) long. If it were closed, the detour would be 5 mi (8 km).

Location

Open in Google Maps
CarriesCounty RD 478
CrossesBlack River
Location3 Miles N E of Republic
RouteCounty Highway 5260
CountyMarquette County
StateMichigan
Coordinates46.42595, -87.92797
Functional classRural Major Collector

Condition and inspection

Good

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

ComponentRatingMeaning
Channel and channel protection8 Very GoodNo problems noted.
Culvert8 Very GoodNo problems noted.
Last inspectionOctober 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation8: Equal to present desirable criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating106.5 US tons
Inventory rating78.6 US tons

Structure

Structure typeCulvert
MaterialConcrete
DeckNot applicable
Main spans1
Design loadGreater than HL 93
Structure length47 ft (14.3 m)
Longest span47 ft (14.3 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic44 (2019)
Projected traffic68 by 2039
Trucks4%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed5 mi (8 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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$112,000
NavigationNo navigation control on waterway

Frequently asked questions

When was County RD 478 over Black River built?

It was built in 2019, making it 6 years old in 2025.

What condition is County RD 478 over Black 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 October 2023.

How much traffic does County RD 478 over Black River carry?

About 44 vehicles per day (2019 count), of which roughly 4% are trucks.

How long is County RD 478 over Black River?

The structure is 47 ft (14.3 m) long with a longest span of 47 ft (14.3 m).

Who owns County RD 478 over Black River?

It is owned by the County Highway Agency.