Frozen road operation improvements

Abstract

A research study in 1996-1997, sponsored by the Wisconsin Department of Transportation (WisDOT), was undertaken to develop a computer model to correlate climate and pavement data for the year in progress in order to project when to impose and lift weight restrictions. The research team collected field data relating to weather and road stiffness over two winter-spring periods, which enabled the development of a six-phase computer model integrating weather conditions, heat transfer, roadway stiffness, stress-strain effects, and estimates of pavement damage load (EDL) for a given road 30, 60, 90, or 120 days into the future based on user-supplied average daily temperatures experienced in the year to date. WisDOT?s Bureau of Highway Operations (BOH) used this software, known as UWFROST, during the 1998-1999 and 1999-2000 winter seasons and found the software?s fall freezing and spring thawing projections to be quite accurate for normal winters. Since this study was conducted, additional data have been collected using frost tubes to declare the roads frozen and then unfrozen. Changes in Wisconsin climate have also been noted which will affect the model. More data have been collected at the national level, which relates pavement material moduli to temperature. All of the data needs to be integrated into an updated version of the model. However, the project investigator, Peter J. Bosscher, passed away unexpectedly and a search through his records indicated that he was the only one who could make changes to UWFROST since he created it alone. Certain materials related to the project have been extracted from his files and are presented in this report as Appendix A - frozen road declaration history and Appendix B - ground truth information (frost tube data).