Structure LONG-15TH-LAMP · Boulder County, CO
Carries 15th Avenue over Oligarchy Ditch, 100 Ft W Of Lamplighte DR.
Set by its lowest-rated component: Deck and Superstructure at 6 of 9.
How ratings work22 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 rigid-frame bridge.
| State | Colorado |
| County | Boulder |
| Location | 100 Ft W Of Lamplighte DR |
| Carries | 15th Avenue |
| Crosses | Oligarchy Ditch |
| Coordinates | 40.18494, -105.09175 |
| Material | Concrete |
| Design | Frame |
| Total Length | 21.7 ft (6.6 m) |
| Max Span | 20.3 ft (6.2 m) |
| Deck Width | 55.4 ft (16.9 m) |
| Deck Area | 111.5 sq m |
| Main Spans | 1 |
| Year Built | 1989 |
| Avg Daily Traffic | 450 (2023) |
| Truck Traffic | 6% |
| Lanes On Bridge | 2 |
| Last Inspection | January 2025 |
| Inspection Frequency | Every 24 months |
| Owner | City/Municipal Highway Agency |
| Historical Significance | Bridge is not eligible for the National Register |
| Scour Critical | 8 — Stable, low risk |
| Structure Number | LONG-15TH-LAMP |
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.