SH 21 over Chapman Creek
Good Condition38 years old1,200 vehicles/day
Location
| State | Idaho |
| County | Boise |
| Location | 18.7 Ne. Lowman |
| Carries | SH 21 |
| Crosses | Chapman Creek |
| Coordinates | 44.13611, -115.31417 |
Condition Ratings
| Overall Condition | Good |
| Deck | 7 (Good) |
| Superstructure | 8 (Very Good) |
| Substructure | 8 (Very Good) |
| Channel/Waterway | 8 (Very Good) |
| Scour Critical | 8 — Stable, low risk |
Physical Characteristics
| Material | Prestressed Concrete |
| Design | Stringer/Multi-beam |
| Total Length | 169.9 ft (51.8 m) |
| Max Span | 55.1 ft (16.8 m) |
| Deck Width | 33.8 ft (10.3 m) |
| Deck Area | 533.5 sq m |
| Main Spans | 3 |
| Year Built | 1988 |
Traffic
| Avg Daily Traffic | 1,200 (2023) |
| Truck Traffic | 9% |
| Lanes On Bridge | 2 |
Inspection & Ownership
| Last Inspection | October 2024 |
| Inspection Frequency | Every 48 months |
| Owner | State Highway Agency |
| Historical Significance | Historical significance is not determined |
| Structure Number | 000000000012915 |