Can Spring Load Restrictions on Low-Volume Roads Be Shortened Without Increasing Road Damage? (05-2690)**
Maureen A. Kestler, USDA Forest Service
Richard L. Berg, FROST Associates
John E. Haddock, Purdue University

Major highways are designed to withstand heavy vehicles and high volumes of traffic year round. However, low volume roads in seasonal frost areas are highly susceptible to damage from trafficking by heavy vehicles during spring thaw. Conventional practice is to place partial or full spring load restrictions on low volume roads during spring thaw. This practice will reduce damage significantly. However, companies whose livelihood depends on trucking can suffer major economic losses as they await removal of load restrictions. Using reduced tire pressure constitutes a less conventional road usage technique that can also contribute toward reducing springtime damage. Reducing tire pressure generally appears to be less effective than reducing load. Nevertheless, it does appear that the load restriction window can be reduced in duration by implementing a reduction in tire pressure for a short duration starting toward the latter part of the standard spring load restriction. Using a mechanistic pavement design and evaluation model for seasonal frost areas that had been under development by the US Army Corps of Engineers, this paper discusses the development of a critical combination of load and tire pressure reduction that contributes toward optimizing the balance between minimizing springtime road damage and minimizing disruption to local economies caused by load restrictions.