US Bridges

S 200 over Flat Creek

Fair

Lewis and Clark County, Montana · 16M SW Simms · Structure no. P00024111+02361

Built
1986
39 years old
Condition
Fair
inspected December 2023
Type
Culvert
Steel
Length
41 ft
2 main spans
Daily traffic
1,507
2023 count
Owner
State
State Highway Agency

About this bridge

S 200 over Flat Creek is a steel culvert carrying S 200 over Flat Creek in Lewis and Clark County, Montana. It was built in 1986, so it is 39 years old, younger than the Montana average of 47 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 1,507 vehicles a day, roughly 11% of them trucks, projected to reach 1,582 by 2043. The structure is 41 ft (12.5 m) long. If it were closed, the detour would be 55.3 mi (89 km).

Location

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CarriesS 200
CrossesFlat Creek
Location16M SW Simms
RouteState Highway 200
CountyLewis and Clark County
StateMontana
Coordinates47.30345, -112.122
Functional classRural Principal Arterial - Other

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Culvert6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionDecember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating99 US tons
Inventory rating94 US tons

Structure

Structure typeCulvert
MaterialSteel
DeckNot applicable
Main spans2
Design loadHL 93
Structure length41 ft (12.5 m)
Longest span15 ft (4.6 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,507 (2023)
Projected traffic1,582 by 2043
Trucks11%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed55.3 mi (89 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—
NavigationNo navigation control on waterway

Frequently asked questions

When was S 200 over Flat Creek built?

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

What condition is S 200 over Flat Creek 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 December 2023.

How much traffic does S 200 over Flat Creek carry?

About 1,507 vehicles per day (2023 count), of which roughly 11% are trucks.

How long is S 200 over Flat Creek?

The structure is 41 ft (12.5 m) long with a longest span of 15 ft (4.6 m).

Who owns S 200 over Flat Creek?

It is owned by the State Highway Agency.