Hauling with Full Axle Weights and Reduced Tire Pressures on Weight-Restricted Roads in British Columbia

Abstract

In North America, imposition of seasonal weight restrictions on thaw-weakened secondary roads may interrupt transport of raw materials to processing facilities for 6 to 12 weeks or even longer. This annual disruption forces processing facilities to operate from stockpiled inventory and typically results in large extra costs for both the processing facility and trucks. The Forest Engineering Research Institute of Canada (FERIC) has been investigating the potential for shortening the weight restriction period (i.e., lengthening the period for hauling with full, legal weights) on secondary roads by hauling with road-friendly trucks. FERIC developed a modeling process to estimate when fully loaded trucks equipped with road-friendly technologies, such as multiple axle groups, large tires, or tire pressure control systems (TPCS), could resume hauling on thaw-weakened pavements without accelerating pavement damage. From 2000 to 2003, FERIC used this modeling process to conduct full-scale tests on a variety of thin pavements in British Columbia, Canada. During these tests, fully loaded log trucks were able to haul during the last 3 to 5 weeks of the weight restriction period with no measurable increase in pavement rutting or cracking. In 2004, the British Columbia Ministry of Transportation introduced a program to exempt trucks operating with TPCS from seasonal weight restrictions on approved roads in British Columbia. FERIC, in cooperation with several forest companies, conducted operational hauling under the new program in spring 2004 and 2005. The operations experienced from 2 to 8 weeks extra hauling during the weight restriction period, with no acceleration of road damage.