Accurate vertical clearance documentation is essential for OS/OW permit applications. This guide covers professional techniques for surveying overheight constraints using LiDAR and complementary tools.
Equipment Overview
**LiDAR Range Finders** — Professional units from Leica, Trimble, or Bosch provide accurate distance measurements to overhead obstacles.
**Survey-Grade GPS** — Records precise location for each measurement point.
**Camera Equipment** — High-resolution photos document conditions and support permit applications.
Measurement Protocol
**1. Approach Assessment** — Evaluate the obstacle from 500 feet out. Note any grade changes, pavement conditions, or obstructions.
**2. Multi-Point Measurement** — Take clearance readings at multiple points across the lane. Overhead wires and old bridges often sag in the center.
**3. Edge-to-Edge Documentation** — Record clearances at both edges and center. Your load may need to use the full lane width.
**4. Temperature Consideration** — Wire sag varies with temperature. Note ambient conditions during survey.
**5. Photo Documentation** — Capture wide-angle context shots and close-up detail images with visible measurement markers.
Common Pitfalls
- Measuring only the center point (missing edge variations)
- Ignoring temporary conditions (construction, seasonal decorations)
- Insufficient photo documentation for permit reviewers
- Not recording GPS coordinates with each measurement
Integration with RoadScope
RoadScope accepts LiDAR data imports and automatically associates clearance measurements with POI locations. The platform validates measurement consistency and flags potential issues before permit submission.