SH 55 ML
Carrying SH 55 ML over SOUTH PLATTE RIVER
1.5 MI S OF JCT SH55+US13, Logan, Colorado
Inventory: FHWA NBI 2024 · last ETL August 2026
FHWA NBI record, refreshed with each annual release.
SH 55 ML in Logan, Colorado sits above 31% of rated Colorado bridges on inventory load rating (29 t), while its 1987 build year is earlier than 58% of Logan's recorded-year cohort (182 bridges).
SH 55 ML in Logan, Colorado is rated Good in the FHWA's 2024 National Bridge Inventory. Built in 1987, it carries 3 rated components on the inspecting agency's 0-9 scale, and its weakest reported component scores 7. The lowest applicable rating sets the federal condition category, so this Good result describes the weakest reported component rather than the structure as a whole. No NBI category is a closure decision or a live crossing-safety verdict.
NBI record plate
Structure CO:A-25-AU
LATE-CENTURY · STEEL · MULTI-SPAN · DECK-LED · LOCAL-ADT · STANDARD-LOAD · CAT-GOOD
- LATE-CENTURY 1980–1999
- STEEL Steel
- MULTI-SPAN 2 spans
- DECK-LED Deck-led
- LOCAL-ADT Local ADT
- STANDARD-LOAD Standard load
- CAT-GOOD Good
Inspection-sheet codes from this record’s year, material family, spans, controlling component, ADT, inventory load, and NBI category, not a live closure verdict.
Bridge Snapshot: SH 55 ML
The SH 55 ML bridge in Logan, Colorado carries SH 55 ML over SOUTH PLATTE RIVER. It was built in 1987, making it 39 years old today. The structure is built primarily of steel continuous and spans 2 sections, stretching 54.9 meters (180 feet) end to end. Daily traffic averages 460 vehicles, placing it in the lower-traffic tier of Colorado bridges. It is owned and maintained by State Highway Agency.
The latest FHWA inspection records show a deck rating of 7/9, superstructure at 8/9, substructure at 8/9. The weakest component sits in good condition. No reported major component scores in the Poor range under the current federal condition thresholds.
How SH 55 ML compares
Age against the county: built in 1987, earlier than 105 of Logan's 182 bridges with a recorded construction year (58%), against a county median build year of 1990. Age is not a defect on its own, but it is the population from which future Poor ratings are drawn.
Live comparison across Colorado bridges with a recorded inventory load rating (8,962 of 8,965 rated).
SH 55 ML vs every rated Colorado bridge
Inventory load rating (metric tons), FHWA NBI, this state
29 Top 69% higher than 31% of 8,962 bridges
rated Colorado bridges, bucketed by value
Each bar is a band; taller bars hold more bridges. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count and share, and where it sits relative to this entry.
Source FHWA National Bridge Inventory · August 2026
Condition Ratings
Full 0–9 scale + sufficiency-rating breakdown: how condition ratings work.
Reported 0–9 component ratings from the FHWA NBI. The highlighted component is the lowest reported input to this record’s current condition category; it is not a closure or live crossing-safety decision.
Logan inventory by recorded NBI category
Exclusive Good/Fair/Poor bands across all 182 bridges in this county. Orthogonal to this structure's component profile above: a county catalog share, not a live crossing-safety verdict.
Structural Details
- Year Built
- 1987
- Material
- Steel Continuous
- Number of Spans
- 2
- Structure Length
- 54.9 m (180 ft)
- Deck Width
- 11.1 m (36 ft)
- Owner
- State Highway Agency
- Avg Daily Traffic
- 460 vehicles/day
- Structure Number
- A-25-AU
Condition Analysis
- • The deck (driving surface) is in good condition (7/9), showing no significant deterioration.
- • At 8/9, the superstructure (beams and supports above the deck) is in good shape and shows no significant wear.
- • The substructure (piers and abutments) is in good condition (8/9), showing no significant deterioration.
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗How to read this record
This page shows what the last federal inspection recorded, not whether SH 55 ML 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 SH 55 ML against other structures in Logan and across Colorado. Colorado 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 SH 55 ML?
SH 55 ML in Logan, Colorado has a deck rating of 7/9, superstructure rating of 8/9, and substructure rating of 8/9 on the FHWA's 0–9 scale.
How often is SH 55 ML inspected?
SH 55 ML'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 460 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. SH 55 ML is currently shown as Good condition from its component ratings; that category is not a live closure or safety decision.
What is the inventory load rating for SH 55 ML?
SH 55 ML has an NBI inventory load rating of 29.4 metric tons.
Who is responsible for maintaining SH 55 ML?
SH 55 ML is owned and maintained by State Highway Agency.
How old is SH 55 ML and does age affect safety?
SH 55 ML was built in 1987, making it 39 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.
Share this inspection record
Send this source-bounded record or download its data card. An NBI condition category is not a closure or live crossing-safety verdict.
Every figure on PlainBridges is rendered directly from federal source data, no number is typed in by an editor. Component ratings, ADT, and condition category on this page are copied from the NBI record for this structure; no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 2024 NBI release. NBI condition categories reflect the latest reported inventory record, not a live safety, closure, or travel decision.