During the spring thaw, a soft layer below the pavement and above the frost line can create weakness in the pavement. This is most prominent on routes that are designated as seasonal and the shoulder portion of all routes.
For this reason, during the period of weight restriction a number of precautions are taken in order to protect the condition of MDOT jurisdiction infrastructure. First, reduced weight limits are in effect for seasonal routes. Seasonal routes are shown on the MDOT Truck Operators' Map. Signs are typically posted indicating seasonal limits on these routes. Secondly, overweight permits are not issued for any MDOT jurisdiction routes. Lastly, in order to protect shoulder conditions, permits for vehicles or loads exceeding 14 feet in width are not issued. Certain emergency situations may receive exceptions to these guidelines.
For additional information, see Truck Weight and Vehicle Restrictions.