Many forestry roads are built to secondary road specifications, especially in forest blocks in the 1,000 to 15,000 ha range. They are unsealed, permanent one or two-lane roads constructed to a high standard.
- Carry between 20 and 80 heavy vehicles per day or between 60,000 to 250,000 tonnes per year
- On flat and rolling terrain, have a road width of 7-8 m, desirable maximum adverse grades of 10% or 12% for short distances, and are designed for a speed of 50 km/hr
- On mountainous terrain, have a road width of 6-7 m, are designed for a speed of 40 km/hr, and desirable maximum adverse grades of 12% or 14% for short distances.
However, the road width is commonly reduced to 4.5-5 m, to reduce construction costs. In this case, full-width sections are required at regular intervals to allow opposing traffic to pass. Consider keeping road grades for 50 Max and HPMV trucks to 12.5% adverse loaded for all terrain unless the road surface is designed for these units. Also, incorporate more width on corners for off-tracking 50 Max and HPMV than for standard 4 axle trailer units.