1. Unsealed Road Deterioration
Christopher R. Bennett
Director - Data Collection Ltd.
The World Bank

2. Roughness and Gravel Thickness
Roughness Function of: - Daily Traffic - Grading Frequency - Material Properties - Rainfall - Rise & Fall and Curvature
Maximum Roughness
Minimum Roughness
Gravel Function of: - Daily Traffic - Material Properties - Rainfall - Rise & Fall and Curvature

3. Minimum and Maximum Roughness
100 ADT
365 Days Gradings
1095 Days Gradings
10 ADT
365 Days Gradings
100 ADT
30 Days Gradings
400 ADT

4. Rural Transport Infrastructure Notes
RT1 - Typical Unpaved Roads: Roughness Predicted by the HDM-III Model
RT2 - Unpaved Roads: Roughness Estimation by Subjective Evaluation
RT3 - Paving of Unpaved Roads: Economically Justified Paving Costs

5. DETOUR Model
The Deterioration of Unpaved Roads Model (DETOUR) implements in MS-Excel the road deterioration relationships for unpaved roads of the Highway Development and Management Model (HDM-4) and is designed primarily for engineered unpaved roads, of either gravel or earth surfacing.

6. RED Model
The Roads Economic Decision Model (RED ) is a customized MS-Excel model for the economic evaluation of low volume roads.