T456 Old Mill Run
Carrying T456 Old Mill Run over MILL RUN
1 MI.W.OF ALTOONA, Blair, Pennsylvania
Inventory: FHWA NBI 2024 · last ETL August 2026
FHWA NBI record, refreshed with each annual release.
T456 Old Mill Run in Blair, Pennsylvania sits above 7% of rated Pennsylvania bridges on inventory load rating (20 t), while its 1957 build year is earlier than 73% of Blair's recorded-year cohort (338 bridges).
T456 Old Mill Run in Blair, Pennsylvania is rated Poor in the FHWA's 2024 National Bridge Inventory. Built in 1957, it carries 3 rated components on the inspecting agency's 0-9 scale, and its weakest reported component scores 3. The lowest applicable rating sets the federal condition category, so this Poor 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 PA:000000000005940
INTERSTATE-ERA · PRESTRESS · SINGLE-SPAN · TIED-CTRL · LOCAL-ADT · STANDARD-LOAD · CAT-POOR
- INTERSTATE-ERA 1950–1979
- PRESTRESS Prestressed concrete
- SINGLE-SPAN Single span
- TIED-CTRL Tied control
- LOCAL-ADT Local ADT
- STANDARD-LOAD Standard load
- CAT-POOR Poor
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: T456 Old Mill Run
The T456 Old Mill Run bridge in Blair, Pennsylvania carries T456 Old Mill Run over MILL RUN. It was built in 1957, making it 69 years old today. The structure is built primarily of prestressed concrete and spans 1 section, stretching 12.2 meters (40 feet) end to end. Daily traffic averages 622 vehicles, placing it in the lower-traffic tier of Pennsylvania bridges. It is owned and maintained by County Highway Agency.
The latest FHWA inspection records show a deck rating of 3/9, superstructure at 3/9, substructure at 4/9. The weakest component sits in poor condition. At least one major component here scores 4 or below, which produces a Poor condition classification under FHWA's current reporting rules.
How T456 Old Mill Run compares
Age against the county: built in 1957, earlier than 248 of Blair's 338 bridges with a recorded construction year (73%), against a county median build year of 1983. Age is not a defect on its own, but it is the population from which future Poor ratings are drawn.
Live comparison across Pennsylvania bridges with a recorded inventory load rating (23,297 of 23,299 rated).
T456 Old Mill Run vs every rated Pennsylvania bridge
Inventory load rating (metric tons), FHWA NBI, this state
20 Top 93% higher than 7% of 23,297 bridges
rated Pennsylvania 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.
Blair inventory by recorded NBI category
Exclusive Good/Fair/Poor bands across all 338 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
- 1957
- Material
- Prestressed Concrete
- Number of Spans
- 1
- Structure Length
- 12.2 m (40 ft)
- Deck Width
- 6.6 m (22 ft)
- Owner
- County Highway Agency
- Avg Daily Traffic
- 622 vehicles/day
- Structure Number
- 000000000005940
Condition Analysis
- • The deck (driving surface) is in poor condition (3/9), showing advanced deterioration on the inspecting agency's 0-9 scale.
- • The superstructure (beams and supports above the deck) rates poor at 3/9, with advanced deterioration recorded on the latest inspection.
- • The substructure (piers and abutments) is in poor condition (4/9), showing advanced deterioration on the inspecting agency's 0-9 scale.
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗How to read this record
T456 Old Mill Run is in the federal Poor condition category. That is a component-based result, not a closure order.
- NBI condition ratings reflect the latest record in this annual dataset, not a live status. Current routine inspection intervals are risk-based.
- Understand what Poor condition does and does not mean before drawing conclusions. Poor condition explained
- Compare T456 Old Mill Run against other structures in Blair and across Pennsylvania. Pennsylvania 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 T456 Old Mill Run?
T456 Old Mill Run in Blair, Pennsylvania has a deck rating of 3/9, superstructure rating of 3/9, and substructure rating of 4/9 on the FHWA's 0–9 scale.
How often is T456 Old Mill Run inspected?
T456 Old Mill Run'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 622 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. T456 Old Mill Run is currently shown as Poor condition from its component ratings; that category is not a live closure or safety decision.
What is the inventory load rating for T456 Old Mill Run?
T456 Old Mill Run has an NBI inventory load rating of 20.0 metric tons.
Who is responsible for maintaining T456 Old Mill Run?
T456 Old Mill Run is owned and maintained by County Highway Agency.
How old is T456 Old Mill Run and does age affect safety?
T456 Old Mill Run was built in 1957, making it 69 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.