Load reductions greater than 60 percent appear to be excessive for paved roads. The general national practice for paved roads was to use load reductions ranging from 40 to 50 percent. The WSTC study confirmed this. However, the study lacked the data to make conclusions about unpaved roads. In some situations, many unpaved roads, especially very old roads that were not designed for modern truck loads therefore greater reductions than recommended for paved roads might be warranted.
Local experience becomes very important with unpaved roads.
The WSTC guidelines used to apply and remove load restrictions are based on air temperature. Agencies can determine when to apply load limits by using a Degree-Days Log. A sample of this log is located below. Degree-Days are the number of degrees between some data and the average temperature for a particular day. The average daily temperature.