IRR BIA RTE 18
Carrying IRR BIA RTE 18 over COLORADO RIVER
2.6 MI W OF BIA RTE 1, La Paz, Arizona
Data updated May 2026
FHWA NBI record, refreshed with each annual release.
Bridge Snapshot: IRR BIA RTE 18
The IRR BIA RTE 18 bridge in La Paz, Arizona carries IRR BIA RTE 18 over COLORADO RIVER. It was built in 1981, making it 45 years old today. The structure is built primarily of prestressed concrete continuous and spans 6 sections, stretching 170.7 meters (560 feet) end to end. Daily traffic averages 274 vehicles, placing it in the lower-traffic tier of Arizona bridges. It is owned and maintained by Bureau of Indian Affairs.
The latest FHWA inspection records show a deck rating of 5/9, superstructure at 7/9, substructure at 6/9. The weakest component sits in fair condition. All reported major components score above the Poor range. Its NBI inventory load rating is 39.0 metric tons.
Sourced from the FHWA National Bridge Inventory. See our methodology for refresh cadence and NBI release vintage.
How IRR BIA RTE 18 compares
Live comparison across Arizona.
Historical Sufficiency Rating
PlainBridge-computedFHWA discontinued this calculated item; it does not determine current condition, funding eligibility, posting, or closure. How the historical reference is calculated.
Condition Ratings
Full 0–9 scale + sufficiency-rating breakdown: how condition ratings work.
Structural Details
- Year Built
- 1981
- Material
- Prestressed Concrete Continuous
- Number of Spans
- 6
- Structure Length
- 170.7 m (560 ft)
- Deck Width
- 10.5 m (34 ft)
- Owner
- Bureau of Indian Affairs
- Avg Daily Traffic
- 274 vehicles/day
- Structure Number
- 00000000000H042
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗Condition Analysis
- • At 5/9, the deck (driving surface) shows fair condition, with minor wear flagged for upkeep.
- • The superstructure (beams and supports above the deck) is in good condition (7/9), showing no significant deterioration.
- • The substructure (piers and abutments) is in fair condition (6/9), with minor deterioration that may require routine maintenance.
How to read this record
This page shows what the last federal inspection recorded, not whether IRR BIA RTE 18 is safe to cross today. Here is how to use it.
- NBI condition ratings reflect the latest record in this annual dataset, not a live status. Current routine inspection intervals are risk-based.
- Learn how the 0–9 condition scale and Good/Fair/Poor categories are defined. How condition ratings work
- Compare IRR BIA RTE 18 against other structures in La Paz and across Arizona. Arizona bridges
- Noticed visible damage or a safety concern? Report it to the agency that owns the bridge, or call 911 in an emergency. How to report a bridge
Condition codes come straight from the FHWA National Bridge Inventory and are not a real-time safety judgment. Only the owning agency, a state DOT, county, or other owner, can post, restrict, or close a bridge.
Frequently Asked Questions
What do the condition ratings mean for IRR BIA RTE 18?
IRR BIA RTE 18 in La Paz, Arizona has a deck rating of 5/9, superstructure rating of 7/9, and substructure rating of 6/9 on the FHWA's 0–9 scale.
How often is IRR BIA RTE 18 inspected?
IRR BIA RTE 18's responsible agency sets its routine interval under FHWA's risk-based inspection rules; this page does not expose the scheduled interval. It carries about 274 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. IRR BIA RTE 18 is currently shown as Fair condition from its component ratings; that category is not a live closure or safety decision.
What is the inventory load rating for IRR BIA RTE 18?
IRR BIA RTE 18 has an NBI inventory load rating of 39.0 metric tons.
Who is responsible for maintaining IRR BIA RTE 18?
IRR BIA RTE 18 is owned and maintained by Bureau of Indian Affairs.
How old is IRR BIA RTE 18 and does age affect safety?
IRR BIA RTE 18 was built in 1981, making it 45 years old.
Disclaimer: Bridge condition data is from the FHWA NBI and reflects the last reported inspection. A Poor condition rating is not a live declaration that a bridge is closed or unsafe for travel. For current closure, posting, or safety information, contact the responsible transportation agency.
Every figure on PlainBridge is rendered directly from federal source data, no number is typed in by an editor. This page draws directly on federal source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.