US Bridges

IRR/US-491 over Unnamed Waterway

Fair

San Juan County, New Mexico · 43.2 MI N of JCT I-40 · Structure no. 000000000007569

Built
1975
50 years old, rebuilt 2014
Condition
Fair
inspected May 2022
Type
Culvert
Concrete
Length
27 ft
2 main spans
Daily traffic
5,936
2023 count
Owner
State
State Highway Agency

About this bridge

IRR/US-491 over Unnamed Waterway is a concrete culvert carrying IRR/US-491 over Unnamed Waterway in San Juan County, New Mexico. It was built in 1975 and reconstructed in 2014, so it is 50 years old, younger than the New Mexico average of 51.5 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 5,936 vehicles a day, roughly 17% of them trucks, projected to reach 8,072 by 2043. The structure is 27 ft (8.3 m) long. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesIRR/US-491
CrossesUnnamed Waterway
Location43.2 MI N of JCT I-40
RouteU.S. Route 491
CountySan Juan County
StateNew Mexico
Coordinates36.08688, -108.69065
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 inspectionMay 2022
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating42.9 US tons
Inventory rating35.7 US tons

Structure

Structure typeCulvert
MaterialConcrete
DeckNot applicable
Main spans2
Design loadHS 20
Structure length27 ft (8.3 m)
Longest span12 ft (3.7 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic5,936 (2023)
Projected traffic8,072 by 2043
Trucks17%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

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 IRR/US-491 over Unnamed Waterway built?

It was built in 1975, making it 50 years old in 2025. It was reconstructed in 2014.

What condition is IRR/US-491 over Unnamed Waterway 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 May 2022.

How much traffic does IRR/US-491 over Unnamed Waterway carry?

About 5,936 vehicles per day (2023 count), of which roughly 17% are trucks.

How long is IRR/US-491 over Unnamed Waterway?

The structure is 27 ft (8.3 m) long with a longest span of 12 ft (3.7 m).

Who owns IRR/US-491 over Unnamed Waterway?

It is owned by the State Highway Agency.