The opportunities for intelligent transportation systems to assist with spring load restrictions and winter weight premiums

Pavements are especially vulnerable to deterioration throughout the spring thaw. During this time of year, as the thaw progresses, the pavement structure becomes weak due to saturation and differential thaw. Damage can occur in both the surface asphalt layer but also in the base, sub-base and subgrade layers depending on the degree of saturation and the degree of thawing. The effects of frost action and thaw weakening can be both costly and disruptive for transportation agencies and their users. Load restrictions have become a common practice for many Transportation agency Maintenance and Operation departments in Canada, in an attempt to limit damage to the pavement structure. The spring load restrictions and winter weight premiums reduce pavement distress caused by the trucks travelling on the weakened structure. Determining when to implement and lift load restrictions has historically been done through selection of a fixed date, visual inspection by experienced maintenance staff, calculation of a Thaw Index or by monitoring frost depths. Intelligent Transportation Systems (ITS) include the application of technology to address transportation issues. This paper will discuss the results of the Research and Development project funded by Transport Canada that looked at the use of ITS to assist with variable load restrictions. Variable load restrictions include Seasonal Load Restrictions (SLR) and Winter Weight Premiums (WWP). The paper will outline the process that the project followed and the results of the various stages, including a discussion on the data needs for pavement planning, design and operations and maintenance and illustrate how ITS can assist the provision of data for SLR and WWP as well as other pavement lifecycle requirements. The paper will discuss the type of monitoring equipment required in the field, the central system functionality required to evaluate the data and make recommendations on timing of implementation and lifting and how the information can be disseminated to the various commercial agencies.