US Bridges

Route 497 over Sturgeon River

Fair

Delta County, Michigan · .5 MI N of Nahma JCT · Structure no. 000000000002139

Built
2008
17 years old
Condition
Fair
inspected July 2023
Type
Truss - Thru
Steel
Length
119 ft
1 main span
Daily traffic
55
2021 count
Owner
County
County Highway Agency

About this bridge

Route 497 over Sturgeon River is a steel truss - thru carrying Route 497 over Sturgeon River in Delta County, Michigan. It was built in 2008, so it is 17 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 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 55 vehicles a day, roughly 7% of them trucks, projected to reach 61 by 2041. The structure is 119 ft (36.3 m) long and 30 ft wide. If it were closed, the detour would be 11.2 mi (18 km).

Location

Open in Google Maps
CarriesRoute 497
CrossesSturgeon River
Location.5 MI N of Nahma JCT
RouteCounty Highway 0
CountyDelta County
StateMichigan
Coordinates45.85074, -86.66881
Functional classRural Minor 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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation7: Better than present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating75.4 US tons
Inventory rating45 US tons

Structure

Structure typeTruss - Thru
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20 + Mod
Structure length119 ft (36.3 m)
Longest span113 ft (34.4 m)
Deck width30 ft (9 m)
Roadway width27 ft (8.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic55 (2021)
Projected traffic61 by 2041
Trucks7%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed11.2 mi (18 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 Route 497 over Sturgeon River built?

It was built in 2008, making it 17 years old in 2025.

What condition is Route 497 over Sturgeon River 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 July 2023.

How much traffic does Route 497 over Sturgeon River carry?

About 55 vehicles per day (2021 count), of which roughly 7% are trucks.

How long is Route 497 over Sturgeon River?

The structure is 119 ft (36.3 m) long with a longest span of 113 ft (34.4 m) and a deck 30 ft wide.

Who owns Route 497 over Sturgeon River?

It is owned by the County Highway Agency.