Alignment of Weight Restrictions on Nine-Month Primary Highways to Mitigate Climate Impacts of Earlier Spring

Saskatchewan’s Ministry of Highway and Infrastructure (MHI) has a highway vehicle weight management system to maximize highway infrastructure utilization for economic activities while protecting highways to ensure a longer service life. The provincial highway system is generally managed in three allowed vehicle weight categories: i) Primary highways with year round access, ii) secondary highways that are weight restricted during early spring, and iii) nine-month primary highways that allow primary weight for 9 months and secondary weight for the remaining three spring months. The categories were established according to highway pavements’ structure capability to handle vehicle weight. The weight restriction on secondary and nine-month primary highways is mainly to protect these lower standard pavements from spring-thaw damage. The secondary highways are subject to the spring weight restriction based on weather triggers (thermistor data). However, to allow for planning freight operations, the nine-month primary follows a fixed schedule where the weight is reverted to secondary for three spring months every year. MHI conducted a study to evaluate if the timing of the three-month secondary weight reversion for nine-month primary highways could be changed to align better with early spring-thaw period. Extensive analysis of historical temperature data, historical spring weight restriction dates, and Benkelman Beam Deflection data from various locations in the province was conducted. The study concluded that due to the different geographical and climatic conditions in the province, highways in the south of the province are more vulnerable from early spring-thaw than those in the north. While the current timing of the three-month secondary weight reversion for nine-month primary highways creates an unacceptable risk for highways in the south, they were found adequate for highways in the north. As a result, a new policy has implemented the secondary weight reversion 15 days earlier for nine-month primary highways in the south than in the north.


  • English

Media Info

  • Media Type: Web
  • Pagination: 1 PDF file, 1.1 MB, 14p.
  • Monograph Title: TAC 2018: Innovation and Technology: Evolving Transportation - 2018 Conference and Exhibition of the Transportation Association of Canada

Subject/Index Terms

Filing Info

  • Accession Number: 01683268
  • Record Type: Publication
  • Source Agency: Transportation Association of Canada (TAC)
  • Files: ITRD, TAC
  • Created Date: Oct 16 2018 2:04PM