Why Grade Matters
Grade is one of the most critical and underestimated constraints in heavy haul route planning. Loaded transport combinations have strict grade limits for both braking control on descents and power requirements on climbs.
The Grade Profile
RoadScope automatically generates a grade profile for every route using a combination of NBI bridge data, government elevation datasets, and field-captured GPS elevation. The profile shows:
- Maximum grade percentage
- Sustained grade length (grades >3% sustained over 0.5km are flagged)
- Adverse grade pairs (uphill followed immediately by steep descent)
Grade Thresholds
**Typical limits by configuration:**
- Standard semi combination: 6-8% maximum
- Multi-axle platform with heavy load: 4-6% maximum
- Self-propelled modular transporter (SPMT): 3-4% maximum
Consult your carrier and pilot car operator for configuration-specific limits.
Integrating Field Grade Data
When surveying, RoadScope records GPS elevation at each POI. For critical grade segments, you can add manual grade observations with a clinometer reading for more precise documentation.
Grade in Permit Documentation
Many permit offices require grade documentation for loads above certain weight thresholds. RoadScope includes grade data in Full Reports automatically.