logo: Ag Engineering Edge: Answers to questions about structures, ventilation, soil, water, waste, energy, machinery, and safety.

Ten commandments of a good road

Probably the most used and abused part of any farm is the driveway and access roads. A well-designed road will last a long time. Water causes more damage to roads than poor materials, heavy traffic or adverse weather conditions. Here are 10 "commandments" you may find helpful in keeping your farm roads in good condition.

  1. Get water away from the road.
    A good surface drainage system has four main parts: road crown, shoulders, ditches, and culverts. The crown and shoulders stop water infiltration into the road surface by diverting the water to the ditches. Ditches and culverts steer water away from the roadway to prevent damage to the road base. They should be kept clean and protected from erosion.
  2. Build a firm foundation.
    A roadway wears out from the top, but it falls apart from the bottom. Road materials that will give a stable foundation have negligible soil settlement with a change in moisture content, and will not deform excessively under repeated loads when either wet or dry.
  3. Use the best soils available.
    The adage "pay me now or pay me later" applies here. The quality of soils used often depends on local availability and cost. But don't cut corners by using inferior base material that will need lots of maintenance and costly rehabilitation during the road's life.
  4. Compact soils well.
    The more dense the material is, the stronger it is. Well-graded soils having an even distribution of particle sizes compact better than soils with mostly one particle size. Crushed or angular particles compact better than rounded particles of the same size. Soils must be moist for best compaction.
  5. Design for winter maintenance.
    If ditches are wide enough to store expected snowfall, they likely will handle spring thaws and heavy water flows. Use a minimum of 1 percent grade for drainage purposes and not greater than 10 percent grade, which makes vehicle maneuvering difficult. Consider safety in the road design. A driver should be able to see 75-100 feet up the road for every 10 MPH of speed.
  6. Build for traffic loads and volumes.
    A rule of thumb is to design the road for the largest vehicle that will use it under normal operations. A good all-weather farm road can be made using a mixture of ¾"-3" crushed stone laid down in two 6" layers, and topped with a 4" thick layer of "bank-run" gravel, ½"-1" crushed stone, or limestone screenings. Wet and pack each layer with a wheel tractor or other heavy wheeled vehicle.
  7. Pave only roads that are ready.
    Don't pave dirt or gravel roads just to get rid of dust problems. Be sure the road is well-built first, with adequate drainage, or the paving will be a waste of money.
  8. Build from the bottom up.
    A road that has a poor base and poor drainage cannot be adequately improved with a top dressing of gravel or new pavement.
  9. Protect your investment.
    Roads need regular maintenance to keep them from falling apart. Maintenance includes blading, shaping and patching the road surface, cleaning and repairing ditches and culverts, cutting brush, trees and grass along the road, and repair of roadside erosion.
  10. Keep good records.
    Recording what type of work was done on roads, when, and what materials were used can help a lot in making sound decisions later on.