SOURDOUGH RD
Carrying SOURDOUGH RD over SWEET GRASS CREEK 027
13M NE BIG TIMBER, Sweet Grass, Montana
FHWA NBI inspection record for this structure. Condition ratings, inventory load rating, span, deck width, and average daily traffic refresh annually with each NBI release.
Bridge Snapshot: SOURDOUGH RD
The SOURDOUGH RD bridge in Sweet Grass, Montana carries SOURDOUGH RD over SWEET GRASS CREEK 027. It was built in 1997, making it 29 years old today. The structure is built primarily of prestressed concrete and spans 1 section, stretching 18.3 meters (60 feet) end to end. Daily traffic averages 100 vehicles, placing it in the lower-traffic tier of Montana bridges. It is owned and maintained by County Highway Agency, the entity responsible for routine inspections and any needed repairs.
The latest FHWA inspection records show a deck rating of 7/9, superstructure at 7/9, substructure at 7/9 on the 0–9 NBI scale, where 9 is excellent and 0 is failed. The weakest component sits in good condition, which drives the overall status of this bridge. No major component scores in the poor range, so the bridge is not classified as structurally deficient under federal criteria. Its NBI inventory load rating is 29.0 metric tons — the load level the structure is rated to carry at inventory (long-term) level.
In a county that maintains hundreds of NBI-tracked bridges, SOURDOUGH RD is one data point in a Montana inventory that FHWA inspects on a two-year cycle (more often when ratings fall). Bridge age alone is not a reliable safety signal — a 29-era structure can outperform a newer one when maintenance is consistent, materials are sound, and traffic loads stay within design limits. Use the condition ratings above, the sufficiency score, and the structurally-deficient flag together to read the bridge's real status, and check the linked county and state pages to see how this bridge ranks against its peers.
Every figure on this page comes directly from the Federal Highway Administration National Bridge Inventory (NBI), the public dataset that catalogs more than 617,000 highway bridges across the United States and is updated annually from the records that each state Department of Transportation submits to the FHWA. The condition codes use the standardized FHWA Recording and Coding Guide, the same scale that determines federal eligibility for the Highway Bridge Program and the Surface Transportation Block Grant set-aside for off-system bridges. A "structurally deficient" classification under those federal criteria is a maintenance and funding flag, never a closure order; states keep deficient bridges open with load posting, weight limits, or accelerated inspection cycles until rehabilitation or replacement is funded. See our methodology for refresh cadence and the exact NBI release vintage powering each record.
How SOURDOUGH RD compares
NBI inventory load rating (metric tons) and structural-deficiency status compared across Montana, computed live from the FHWA NBI.
Condition Ratings
Ratings are on a 0–9 scale: 9 = Excellent, 7–8 = Good, 5–6 = Fair, 3–4 = Poor, 0–2 = Critical/Failed. Sufficiency rating (0–100) combines structural adequacy, functional obsolescence, and essentiality.
Structural Details
- Year Built
- 1997
- Material
- Prestressed Concrete
- Number of Spans
- 1
- Structure Length
- 18.3 m (60 ft)
- Deck Width
- 6.1 m (20 ft)
- Owner
- County Highway Agency
- Avg Daily Traffic
- 100 vehicles/day
- Structure Number
- L49016006+02001
Location
Data Source
Data from the FHWA National Bridge Inventory (NBI). Bridge inspections are required every two years by federal law. Conditions reflect the most recent inspection.
FHWA NBI Program ↗Guides
Condition Analysis
Built in 1997, this bridge is 29 years old. It carries approximately 100 vehicles per day. Based on the most recent FHWA inspection:
- • The deck (driving surface) is in good condition (7/9), showing no significant deterioration.
- • 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 good condition (7/9), showing no significant deterioration.
Its NBI inventory load rating reflects the load level it is rated to carry.
Frequently Asked Questions
What do the condition ratings mean for SOURDOUGH RD?
Bridge condition ratings use a 0–9 scale set by the Federal Highway Administration (FHWA). Ratings 7–9 indicate good condition with no significant problems. Ratings 5–6 mean fair condition with minor issues. Ratings 3–4 indicate poor condition requiring repair. Ratings 0–2 are critical, meaning the bridge has serious structural problems. SOURDOUGH RD in Sweet Grass, Montana has a deck rating of 7/9, superstructure rating of 7/9, and substructure rating of 7/9.
How often is SOURDOUGH RD inspected?
Federal law requires most highway bridges to be inspected at least every 24 months. Bridges in poor condition or with known issues may be inspected more frequently (every 12 months or less). SOURDOUGH RD is part of the National Bridge Inventory maintained by the FHWA. With 100 vehicles crossing daily, regular inspection is essential.
What does "structurally deficient" mean for a bridge?
A structurally deficient bridge has at least one major component (deck, superstructure, or substructure) rated 4 or below on the FHWA 0–9 scale. This classification does NOT mean the bridge is unsafe for travel — it means the bridge needs repair, rehabilitation, or eventual replacement. Structurally deficient bridges remain open and are monitored. SOURDOUGH RD is not classified as structurally deficient.
What is the inventory load rating for SOURDOUGH RD?
The NBI inventory rating is the load level a bridge is rated to carry for an indefinite period, recorded in metric tons. A lower number means the structure is more load-restricted. SOURDOUGH RD has an inventory load rating of 29.0 metric tons. It is distinct from the FHWA sufficiency rating, a separate 0–100 funding-eligibility score that this dataset does not include.
Who is responsible for maintaining SOURDOUGH RD?
Bridge ownership and maintenance responsibility varies — bridges may be owned by state DOTs, counties, cities, railroads, or federal agencies. SOURDOUGH RD is maintained by County Highway Agency. The FHWA oversees the National Bridge Inventory program and sets inspection standards, but day-to-day maintenance falls to the owning agency. If you notice damage or safety concerns, contact your state DOT or call 911 for emergencies.
How old is SOURDOUGH RD and does age affect safety?
SOURDOUGH RD was built in 1997, making it 29 years old. Bridge age alone does not determine safety — condition depends on materials, design, traffic load, maintenance history, and environmental exposure. Many older bridges remain in good condition due to regular maintenance and reconstruction.
Disclaimer: Bridge condition data is from the FHWA NBI and reflects the last reported inspection. A structurally deficient rating does not mean a bridge is closed or unsafe for travel — it indicates the bridge requires repair or replacement. For current closure or safety information, contact your state DOT.
Read our methodology — how this data is sourced, computed, and verified.
Related
| Publisher | Kiznis Studio |
| Sources | FHWA National Bridge Inventory, public U.S. government datasets |