US-23 SB
Carrying US-23 SB over HURON RIVER DRIVE
0.8 MI N OF M-17, Washtenaw, Michigan
Inventory: FHWA NBI 2024 · last ETL August 2026
FHWA NBI record, refreshed with each annual release.
US-23 SB in Washtenaw, Michigan sits above 32% of rated Michigan bridges on inventory load rating (34 t), while its 1962 build year is earlier than 64% of Washtenaw's recorded-year cohort (262 bridges).
US-23 SB in Washtenaw, Michigan is rated Poor in the FHWA's 2024 National Bridge Inventory. Built in 1962, it carries 3 rated components on the inspecting agency's 0-9 scale, and its weakest reported component scores 4. 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 MI:000000000010870
INTERSTATE-ERA · PRESTRESS · MULTI-SPAN · SUB-LED · HEAVY-ADT · STANDARD-LOAD · CAT-POOR
- INTERSTATE-ERA 1950–1979
- PRESTRESS Prestressed concrete
- MULTI-SPAN 3 spans
- SUB-LED Substructure-led
- HEAVY-ADT Heavy 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: US-23 SB
The US-23 SB bridge in Washtenaw, Michigan carries US-23 SB over HURON RIVER DRIVE. It was built in 1962, making it 64 years old today. The structure is built primarily of prestressed concrete and spans 3 sections, stretching 33.2 meters (109 feet) end to end. Daily traffic averages 37,373 vehicles, placing it in the heavily-trafficked tier of Michigan bridges. It is owned and maintained by State Highway Agency.
The latest FHWA inspection records show a deck rating of 5/9, superstructure at 5/9, substructure at 4/9. The weakest component sits in poor condition. Because at least one major component scores 4 or lower, this bridge falls in FHWA's Poor condition category. That category is not a closure order.
How US-23 SB compares
Age against the county: built in 1962, earlier than 168 of Washtenaw's 262 bridges with a recorded construction year (64%), against a county median build year of 1971. Age is not a defect on its own, but it is the population from which future Poor ratings are drawn.
Live comparison across Michigan bridges with a recorded inventory load rating (11,366 of 11,371 rated).
US-23 SB vs every rated Michigan bridge
Inventory load rating (metric tons), FHWA NBI, this state
34 Top 68% higher than 32% of 11,366 bridges
rated Michigan 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.
Washtenaw inventory by recorded NBI category
Exclusive Good/Fair/Poor bands across all 262 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
- 1962
- Material
- Prestressed Concrete
- Number of Spans
- 3
- Structure Length
- 33.2 m (109 ft)
- Deck Width
- 14.6 m (48 ft)
- Owner
- State Highway Agency
- Avg Daily Traffic
- 37,373 vehicles/day
- Structure Number
- 000000000010870
Condition Analysis
- • The deck (driving surface) rates fair at 5/9, minor deterioration that routine maintenance should address.
- • At 5/9, the superstructure (beams and supports above the deck) shows fair condition, with minor wear flagged for upkeep.
- • 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
US-23 SB 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 US-23 SB against other structures in Washtenaw and across Michigan. Michigan 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 US-23 SB?
US-23 SB in Washtenaw, Michigan has a deck rating of 5/9, superstructure rating of 5/9, and substructure rating of 4/9 on the FHWA's 0–9 scale.
How often is US-23 SB inspected?
US-23 SB'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 37,373 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. US-23 SB 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 US-23 SB?
US-23 SB has an NBI inventory load rating of 34.0 metric tons.
Who is responsible for maintaining US-23 SB?
US-23 SB is owned and maintained by State Highway Agency.
How old is US-23 SB and does age affect safety?
US-23 SB was built in 1962, making it 64 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.