US Bridges

S 16 over Medicine Lake

Fair

Sheridan County, Montana · 1M S Medicine Lake · Structure no. P00022065+06251

Built
1975
50 years old
Condition
Fair
inspected August 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
161 ft
5 main spans
Daily traffic
891
2023 count
Owner
State
State Highway Agency

About this bridge

S 16 over Medicine Lake is a prestressed concrete stringer/multi-beam or girder carrying S 16 over Medicine Lake in Sheridan County, Montana. It was built in 1975, so it is 50 years old, older 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 891 vehicles a day, roughly 10% of them trucks, projected to reach 936 by 2043. The structure is 161 ft (49.1 m) long and 42 ft wide. If it were closed, the detour would be 123.7 mi (199 km).

Location

Open in Google Maps
CarriesS 16
CrossesMedicine Lake
Location1M S Medicine Lake
RouteState Highway 16
CountySheridan County
StateMontana
Coordinates48.479, -104.49747
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionAugust 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry7: Better than present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating48 US tons
Inventory rating31 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans5
Design loadHS 20
Structure length161 ft (49.1 m)
Longest span35 ft (10.7 m)
Deck width42 ft (12.9 m)
Roadway width39 ft (12 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic891 (2023)
Projected traffic936 by 2043
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed123.7 mi (199 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 16 over Medicine Lake built?

It was built in 1975, making it 50 years old in 2025.

What condition is S 16 over Medicine Lake 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 August 2024.

How much traffic does S 16 over Medicine Lake carry?

About 891 vehicles per day (2023 count), of which roughly 10% are trucks.

How long is S 16 over Medicine Lake?

The structure is 161 ft (49.1 m) long with a longest span of 35 ft (10.7 m) and a deck 42 ft wide.

Who owns S 16 over Medicine Lake?

It is owned by the State Highway Agency.