Structure 31200 · Bonneville County, ID
Carries Jackknife Road over Jackknife Creek, 0.9 N. 16.8 E. Grays Lake.
24 ft end to end. Lengths are drawn to scale; at this length a semi-truck would be a speck. Each part is colored by its latest inspection rating. The inventory records lengths but not heights or the layout of the shorter spans, so those are drawn as typical for a box-beam bridge.
| State | Idaho |
| County | Bonneville |
| Location | 0.9 N. 16.8 E. Grays Lake |
| Carries | Jackknife Road |
| Crosses | Jackknife Creek |
| Coordinates | 43.04461, -111.04608 |
| Material | Prestressed Concrete |
| Design | Box Beam - Multiple |
| Total Length | 24.0 ft (7.3 m) |
| Max Span | 22.0 ft (6.7 m) |
| Deck Width | 34.1 ft (10.4 m) |
| Deck Area | 75.9 sq m |
| Main Spans | 1 |
| Year Built | 1976 |
| Avg Daily Traffic | 160 (2023) |
| Truck Traffic | 23% |
| Lanes On Bridge | 2 |
| Last Inspection | September 2024 |
| Inspection Frequency | Every 24 months |
| Owner | County Highway Agency |
| Historical Significance | Historical significance is not determined |
| Scour Critical | Unknown |
| Structure Number | 000000000031200 |
Inspectors rate each major part of a bridge (the deck you drive on, the superstructure of beams that holds it up, and the substructure of piers and abutments beneath) on a 0–9 scale. A bridge's overall condition is its lowest of those ratings, so one deteriorated component makes the whole bridge "poor."
A poor rating is not a closure. It means the bridge is flagged for priority repair or replacement; bridges judged unsafe are closed or posted with weight limits. The waterway (channel) rating is reported, but it does not count toward the overall classification.