US Bridges

US 1 (sr 5) over Niles Channel

Fair

Monroe County, Florida · Summerland Key (mm 25.5) · Structure no. 900117

Built
1981
44 years old
Condition
Fair
inspected August 2023
Type
Segmental Box Girder
Prestressed Concrete Continuous
Length
4,557 ft
39 main spans
Daily traffic
16,900
2024 count
Owner
State
State Highway Agency

About this bridge

US 1 (sr 5) over Niles Channel is a prestressed concrete continuous segmental box girder carrying US 1 (sr 5) over Niles Channel in Monroe County, Florida. It was built in 1981, so it is 44 years old, older than the Florida average of 41.3 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 16,900 vehicles a day, roughly 17% of them trucks, projected to reach 29,322 by 2044. The structure is 4,557 ft (1,389 m) long and 39 ft wide. If it were closed, the detour would be 123.7 mi (199 km).

Location

Open in Google Maps
CarriesUS 1 (sr 5)
CrossesNiles Channel
LocationSummerland Key (mm 25.5)
RouteU.S. Route 1
CountyMonroe County
StateFlorida
Coordinates24.6606, -81.42959
Functional classUrban Other Principal Arterial

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.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionAugust 2023
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 geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating37.8 US tons
Inventory rating29.2 US tons

Structure

Structure typeSegmental Box Girder
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans39
Design loadHL 93
Structure length4,557 ft (1,389 m)
Longest span118 ft (36 m)
Deck width39 ft (11.9 m)
Roadway width36 ft (11 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic16,900 (2024)
Projected traffic29,322 by 2044
Trucks17%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed123.7 mi (199 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkNon-Interstate STRAHNET route

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedOther structural work, including hydraulic replacements
Estimated improvement cost$189,000
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was US 1 (sr 5) over Niles Channel built?

It was built in 1981, making it 44 years old in 2025.

What condition is US 1 (sr 5) over Niles Channel 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 2023.

How much traffic does US 1 (sr 5) over Niles Channel carry?

About 16,900 vehicles per day (2024 count), of which roughly 17% are trucks.

How long is US 1 (sr 5) over Niles Channel?

The structure is 4,557 ft (1,389 m) long with a longest span of 118 ft (36 m) and a deck 39 ft wide.

Who owns US 1 (sr 5) over Niles Channel?

It is owned by the State Highway Agency.