Responding to Climate Change with Rational Approaches for Managing Seasonal Weight Programs in Manitoba

Recent changes in Canada's regional climate have made historic weather and strength recovery trends less reliable predictors of when to start and end spring load restrictions (SLR) and winter weight premiums (WWP). The Manitoba Department of Infrastructure and Transportation (MIT) and FPInnovations have recently developed rational methods for starting and ending these seasonal weight programs in Manitoba. The SLR method links weather-based indices to when test pavements started to weaken, and to when their strength was substantially recovered in the spring. The analysis resulted in the implementation of a new SLR policy with starting and ending thresholds based on cumulative thawing index (CTI). The WWP method links weather-based indices to when the strength of freezing test pavements stabilized, and to when these frozen pavements began to warm and weaken in late winter. Starting and ending thresholds based on cumulative freezing index (CFI) and CTI were recommended as interim thresholds for WWP policy.