US Bridges

SH 55 over Farmers Union Canal

Good

Ada County, Idaho · 1.2 N. of SH 44 · Structure no. 000000000014754

Built
1997
28 years old
Condition
Good
inspected November 2021
Type
Frame
Concrete
Length
29 ft
1 main span
Daily traffic
16,000
2023 count
Owner
State
State Highway Agency

About this bridge

SH 55 over Farmers Union Canal is a concrete frame carrying SH 55 over Farmers Union Canal in Ada County, Idaho. It was built in 1997, so it is 28 years old, younger than the Idaho average of 45.3 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 16,000 vehicles a day, roughly 5% of them trucks, projected to reach 24,000 by 2042. The structure is 29 ft (8.8 m) long and 154 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesSH 55
CrossesFarmers Union Canal
Location1.2 N. of SH 44
RouteState Highway 55
CountyAda County
StateIdaho
Coordinates43.70088, -116.31907
Functional classUrban Other Principal Arterial

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionNovember 2021
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry9: Superior to present desirable criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating87 US tons
Inventory rating52 US tons

Structure

Structure typeFrame
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 25 or greater
Structure length29 ft (8.8 m)
Longest span22 ft (6.7 m)
Deck width154 ft (46.9 m)
Roadway width150 ft (45.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic16,000 (2023)
Projected traffic24,000 by 2042
Trucks5%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was SH 55 over Farmers Union Canal built?

It was built in 1997, making it 28 years old in 2025.

What condition is SH 55 over Farmers Union Canal in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in November 2021.

How much traffic does SH 55 over Farmers Union Canal carry?

About 16,000 vehicles per day (2023 count), of which roughly 5% are trucks.

How long is SH 55 over Farmers Union Canal?

The structure is 29 ft (8.8 m) long with a longest span of 22 ft (6.7 m) and a deck 154 ft wide.

Who owns SH 55 over Farmers Union Canal?

It is owned by the State Highway Agency.