Keeping Springtime Low-Volume Road Damage to a Minimum

Abstract

There are approximately 3 million miles of low-volume roads (LVRs) in the United States, and approximately half of them are located in seasonal frost areas. Limiting or prohibiting loads during spring thaw can keep damage to a minimum. However, methods of determining when to place and remove spring load restrictions, particularly on LVRs, are often highly subjective—if restrictions are imposed at all. In partnership with several other agencies, the U.S. Department of Agriculture Forest Service has been compiling a toolkit of practical low-cost diagnostic techniques for determining conditions under which spring load restrictions should be placed and removed. This paper expands on techniques reported in a previous paper from a TRB low-volume roads conference and reports on further developments of additional methods. Techniques discussed include (a) subsurface instrumentation, (b) lightweight deflectometer, (c) thaw index, (d) climatic thaw predictor model, and (e) length of time. Requirements and equipment needed to use each of the techniques are described, strengths and weaknesses of each are outlined, and recommendations on various combinations of methods are provided to enable road managers to optimize placement of spring load restrictions.