Hazard intensity metric | Skid resistance reductiona | Road marking coverageb | Visibility impairmentc |
---|---|---|---|
Thickness (mm) – related to area density / loading (kg/m2) in some cases | ✓ | ✓ | |
Ash-settling rate (g m−2 h−1) | ✓ | ||
Particle size (μm) | ✓ | ✓ | ✓ |
Colour | ✓ | ✓ | |
Wetness | ✓ | ||
Soluble content | ✓ | ||
Hardness (proxy: ash type) | ✓ | ✓ | ✓ |
Shape (proxy: ash generation method) | ✓ | ✓ | ✓ |