US Bridges

Mason Road over S Br Shiawassee River

Good

Livingston County, Michigan · Sec 34 Howell Twp · Structure no. 000000000005816

Built
1986
39 years old, rebuilt 2022
Condition
Good
inspected April 2024
Type
Box Beam or Girders - Single or Spread
Steel
Length
36 ft
1 main span
Daily traffic
2,760
2020 count
Owner
County
County Highway Agency

About this bridge

Mason Road over S Br Shiawassee River is a steel box beam or girders - single or spread carrying Mason Road over S Br Shiawassee River in Livingston County, Michigan. It was built in 1986 and reconstructed in 2022, so it is 39 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 2,760 vehicles a day, roughly 3% of them trucks, projected to reach 3,368 by 2040. The structure is 36 ft (10.9 m) long and 42 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

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CarriesMason Road
CrossesS Br Shiawassee River
LocationSec 34 Howell Twp
RouteCounty Highway 4750
CountyLivingston County
StateMichigan
Coordinates42.60001, -83.96361
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
Deck8 Very GoodNo problems noted.
Superstructure9 ExcellentNo problems noted.
Substructure8 Very GoodNo problems noted.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionApril 2024
Inspection intervalevery 16 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation8: Equal to present desirable criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating93.9 US tons
Inventory rating72.5 US tons

Structure

Structure typeBox Beam or Girders - Single or Spread
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadGreater than HL 93
Structure length36 ft (10.9 m)
Longest span33 ft (10.2 m)
Deck width42 ft (12.9 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,760 (2020)
Projected traffic3,368 by 2040
Trucks3%
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 Mason Road over S Br Shiawassee River built?

It was built in 1986, making it 39 years old in 2025. It was reconstructed in 2022.

What condition is Mason Road over S Br Shiawassee 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 April 2024.

How much traffic does Mason Road over S Br Shiawassee River carry?

About 2,760 vehicles per day (2020 count), of which roughly 3% are trucks.

How long is Mason Road over S Br Shiawassee River?

The structure is 36 ft (10.9 m) long with a longest span of 33 ft (10.2 m) and a deck 42 ft wide.

Who owns Mason Road over S Br Shiawassee River?

It is owned by the County Highway Agency.