What is Acceptable Survey Tolerance for DOT?
For most state Departments of Transportation (DOT), the acceptable survey tolerance for primary control networks is 1:50,000 (roughly 0.02 feet per 1,000 feet). For topographic features and pavement layout, the horizontal tolerance is strictly 0.10 feet (~30mm), and vertical tolerance is 0.05 feet (15mm).
Data & Tolerance Table
The following table outlines the exact parameters and tolerances associated with this scenario to help you gauge the severity of the geodetic error.
| DOT Construction Element | Horizontal Tolerance | Vertical Tolerance |
|---|---|---|
| Primary Control Network | 0.02 ft (1:50k) | 0.01 ft |
| Bridge Substructure / Piers | 0.03 ft (10mm) | 0.01 ft (3mm) |
| Finished Concrete Pavement | 0.10 ft (30mm) | 0.02 ft (6mm) |
| Earthwork / Rough Grading | 0.50 ft (150mm) | 0.10 ft (30mm) |
📐 Geodetic Formula
Traverse Linear Error of Closure = √(ΔEast² + ΔNorth²) ≤ Allowable Standard (e.g., 1:50,000)
📜 Official Regulatory Compliance Reference
FHWA (Federal Highway Administration) / Individual State DOT Survey Manuals.
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