US Bridges

670th Road over I-80

Fair

Cass County, Iowa · 1.7 Mi. E of Jct. US 71 · Structure no. 000000000018100

Built
1959
66 years old
Condition
Fair
inspected February 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
218 ft
4 main spans
Daily traffic
72
2022 count
Owner
State
State Highway Agency

About this bridge

670th Road over I-80 is a prestressed concrete stringer/multi-beam or girder carrying 670th Road over I-80 in Cass County, Iowa. It was built in 1959, so it is 66 years old, older than the Iowa average of 45.5 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 72 vehicles a day, roughly 10% of them trucks, projected to reach 72 by 2043. The structure is 218 ft (66.4 m) long and 28 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
Carries670th Road
CrossesI-80
Location1.7 Mi. E of Jct. US 71
RouteCounty Highway 0
CountyCass County
StateIowa
Coordinates41.49689, -94.91188
Functional classRural Local

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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Last inspectionFebruary 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry6: Equal to present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating55.3 US tons
Inventory rating19 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans4
Design loadH 15
Structure length218 ft (66.4 m)
Longest span65 ft (19.8 m)
Deck width28 ft (8.6 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic72 (2022)
Projected traffic72 by 2043
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesHighway
Detour if closed3.7 mi (6 km)
TollOn a free road
National Highway SystemNo

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 670th Road over I-80 built?

It was built in 1959, making it 66 years old in 2025.

What condition is 670th Road over I-80 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 February 2023.

How much traffic does 670th Road over I-80 carry?

About 72 vehicles per day (2022 count), of which roughly 10% are trucks.

How long is 670th Road over I-80?

The structure is 218 ft (66.4 m) long with a longest span of 65 ft (19.8 m) and a deck 28 ft wide.

Who owns 670th Road over I-80?

It is owned by the State Highway Agency.