US Bridges

IRR/NM-399 over Arroyo Seco

Fair

Rio Arriba County, New Mexico · 0.85 MI SW of JCT US-84 · Structure no. 000000000008149

Built
1979
46 years old
Condition
Fair
inspected June 2024
Type
Slab
Concrete Continuous
Length
134 ft
4 main spans
Daily traffic
4,798
2023 count
Owner
State
State Highway Agency

About this bridge

IRR/NM-399 over Arroyo Seco is a concrete continuous slab carrying IRR/NM-399 over Arroyo Seco in Rio Arriba County, New Mexico. It was built in 1979, so it is 46 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 4,798 vehicles a day, roughly 11% of them trucks, projected to reach 6,525 by 2043. The structure is 134 ft (40.9 m) long and 40 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesIRR/NM-399
CrossesArroyo Seco
Location0.85 MI SW of JCT US-84
RouteState Highway 399
CountyRio Arriba County
StateNew Mexico
Coordinates35.9716, -106.0572
Functional classUrban Minor 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 inspectionJune 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 geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating71.4 US tons
Inventory rating42.9 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20
Structure length134 ft (40.9 m)
Longest span37 ft (11.3 m)
Deck width40 ft (12.1 m)
Roadway width30 ft (9.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic4,798 (2023)
Projected traffic6,525 by 2043
Trucks11%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$294,000
NavigationNot applicable (no waterway)

Frequently asked questions

When was IRR/NM-399 over Arroyo Seco built?

It was built in 1979, making it 46 years old in 2025.

What condition is IRR/NM-399 over Arroyo Seco 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 June 2024.

How much traffic does IRR/NM-399 over Arroyo Seco carry?

About 4,798 vehicles per day (2023 count), of which roughly 11% are trucks.

How long is IRR/NM-399 over Arroyo Seco?

The structure is 134 ft (40.9 m) long with a longest span of 37 ft (11.3 m) and a deck 40 ft wide.

Who owns IRR/NM-399 over Arroyo Seco?

It is owned by the State Highway Agency.