US Bridges

S 474 over RR

Poor

Missoula County, Montana · 4M SE Frenchtown · Structure no. S00474000+06321

Built
1959
66 years old
Condition
Poor
inspected September 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
184 ft
3 main spans
Daily traffic
1,397
2023 count
Owner
State
State Highway Agency

About this bridge

S 474 over RR is a steel stringer/multi-beam or girder carrying S 474 over RR in Missoula County, Montana. It was built in 1959, so it is 66 years old, older than the Montana average of 47 years.

The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 4 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.

It carries about 1,397 vehicles a day, roughly 1% of them trucks, projected to reach 1,467 by 2043. The structure is 184 ft (56 m) long and 27 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesS 474
CrossesRR
Location4M SE Frenchtown
RouteState Highway 474
CountyMissoula County
StateMontana
Coordinates46.96517, -114.18462
Functional classRural Major Collector

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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure4 PoorAdvanced section loss, deterioration, spalling or scour.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating41 US tons
Inventory rating25 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans3
Design loadHS 15
Structure length184 ft (56 m)
Longest span70 ft (21.3 m)
Deck width27 ft (8.3 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,397 (2023)
Projected traffic1,467 by 2043
Trucks1%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesRailroad
Detour if closed1.9 mi (3 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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$446,000
NavigationNot applicable (no waterway)

Frequently asked questions

When was S 474 over RR built?

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

What condition is S 474 over 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 September 2023.

How much traffic does S 474 over RR carry?

About 1,397 vehicles per day (2023 count), of which roughly 1% are trucks.

How long is S 474 over RR?

The structure is 184 ft (56 m) long with a longest span of 70 ft (21.3 m) and a deck 27 ft wide.

Who owns S 474 over RR?

It is owned by the State Highway Agency.