US 17 ALT
Carrying US 17 ALT over COMBAHEE RIVER
HAMP/COLL CO LN, Colleton, South Carolina
Inventory: FHWA NBI 2024 · last ETL August 2026
FHWA NBI record, refreshed with each annual release.
US 17 ALT in Colleton, South Carolina sits above 40% of rated South Carolina bridges on inventory load rating (26 t), while its 1940 build year is earlier than 88% of Colleton's recorded-year cohort (231 bridges).
US 17 ALT in Colleton, South Carolina is rated Poor in the FHWA's 2024 National Bridge Inventory. Built in 1940, 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 SC:000000000001026
PRE-1950 · CONCRETE · LONG-SPAN-RUN · TIED-CTRL · ARTERIAL-ADT · STANDARD-LOAD · CAT-POOR
- PRE-1950 Pre-1950
- CONCRETE Concrete
- LONG-SPAN-RUN 27 spans
- TIED-CTRL Tied control
- ARTERIAL-ADT Arterial 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 17 ALT
The US 17 ALT bridge in Colleton, South Carolina carries US 17 ALT over COMBAHEE RIVER. It was built in 1940, making it 86 years old today. The structure is built primarily of concrete and spans 27 sections, stretching 246.9 meters (810 feet) end to end. Daily traffic averages 1,300 vehicles, placing it in the moderately-trafficked tier of South Carolina bridges. It is owned and maintained by State Highway Agency.
The latest FHWA inspection records show a deck rating of 5/9, superstructure at 4/9, 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 US 17 ALT compares
Age against the county: built in 1940, earlier than 204 of Colleton's 231 bridges with a recorded construction year (88%), against a county median build year of 1968. Age is not a defect on its own, but it is the population from which future Poor ratings are drawn.
Live comparison across South Carolina bridges with a recorded inventory load rating (9,483 of 9,490 rated).
US 17 ALT vs every rated South Carolina bridge
Inventory load rating (metric tons), FHWA NBI, this state
26 Top 60% higher than 40% of 9,483 bridges
rated South Carolina 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.
Colleton inventory by recorded NBI category
Exclusive Good/Fair/Poor bands across all 231 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
- 1940
- Material
- Concrete
- Number of Spans
- 27
- Structure Length
- 246.9 m (810 ft)
- Deck Width
- 8.4 m (28 ft)
- Owner
- State Highway Agency
- Avg Daily Traffic
- 1,300 vehicles/day
- Structure Number
- 000000000001026
Condition Analysis
- • The deck (driving surface) rates fair at 5/9, minor deterioration that routine maintenance should address.
- • At 4/9, the superstructure (beams and supports above the deck) is in poor shape, with advanced wear on file for this vintage.
- • The substructure (piers and abutments) rates poor at 4/9, with advanced deterioration recorded on the latest inspection.
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗How to read this record
US 17 ALT 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 17 ALT against other structures in Colleton and across South Carolina. South Carolina 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 17 ALT?
US 17 ALT in Colleton, South Carolina has a deck rating of 5/9, superstructure rating of 4/9, and substructure rating of 4/9 on the FHWA's 0–9 scale.
How often is US 17 ALT inspected?
US 17 ALT'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 1,300 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. US 17 ALT 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 17 ALT?
US 17 ALT has an NBI inventory load rating of 26.2 metric tons.
Who is responsible for maintaining US 17 ALT?
US 17 ALT is owned and maintained by State Highway Agency.
How old is US 17 ALT and does age affect safety?
US 17 ALT was built in 1940, making it 86 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.