US Bridges

I-75 Conn over NS & Gtw RR

PoorPosted for load

Monroe County, Michigan · 3.0 MI N Ohio State Line · Structure no. 000000000007154

Built
1938
87 years old
Condition
Poor
inspected December 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
300 ft
7 main spans
Daily traffic
3,200
2013 count
Owner
State
State Highway Agency

About this bridge

I-75 Conn over NS & Gtw RR is a steel stringer/multi-beam or girder carrying I-75 Conn over NS & Gtw RR in Monroe County, Michigan. It was built in 1938, so it is 87 years old, older than the Michigan average of 48.3 years.

The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 3 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. Its operating status is: posted for load restriction.

It carries about 3,200 vehicles a day, roughly 8% of them trucks, projected to reach 7,360 by 2033. The structure is 300 ft (91.4 m) long and 54 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesI-75 Conn
CrossesNS & Gtw RR
Location3.0 MI N Ohio State Line
RouteInterstate 75
CountyMonroe County
StateMichigan
Coordinates41.77346, -83.48669
Functional classRural Minor Arterial

Condition and inspection

Poor

The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

ComponentRatingMeaning
Deck4 PoorAdvanced section loss, deterioration, spalling or scour.
Superstructure3 SeriousLoss of section, deterioration, spalling or scour have seriously affected primary structural components.
Substructure3 SeriousLoss of section, deterioration, spalling or scour have seriously affected primary structural components.
Last inspectionDecember 2024
Inspection intervalevery 12 months
Operating statusPosted for load restriction
ScourBridge not over waterway
Structural evaluation3: Basically intolerable, requiring high priority of corrective action
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating53.6 US tons
Inventory rating32.2 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans7
Design loadHS 20
Structure length300 ft (91.4 m)
Longest span54 ft (16.4 m)
Deck width54 ft (16.5 m)
Roadway width52 ft (16 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,200 (2013)
Projected traffic7,360 by 2033
Trucks8%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway
CrossesRailroad
Detour if closed3.7 mi (6 km)
TollOn a free road
National Highway SystemYes

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—
NavigationNot applicable (no waterway)

Frequently asked questions

When was I-75 Conn over NS & Gtw RR built?

It was built in 1938, making it 87 years old in 2025.

What condition is I-75 Conn over NS & Gtw RR in?

The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in December 2024.

How much traffic does I-75 Conn over NS & Gtw RR carry?

About 3,200 vehicles per day (2013 count), of which roughly 8% are trucks.

How long is I-75 Conn over NS & Gtw RR?

The structure is 300 ft (91.4 m) long with a longest span of 54 ft (16.4 m) and a deck 54 ft wide.

Who owns I-75 Conn over NS & Gtw RR?

It is owned by the State Highway Agency.