Heavy vehicle stability and control performance measures are commonly used as an objective tool for the development of heavy vehicle size and weight policy. In some jurisdictions of Canada, the use of performance measures has expanded to help support screening protocols for non-conforming vehicles under special permit systems. Special permit systems allow for the acceptance of vehicles not covered by standard size and weight policy. A given vehicle may be designed for overweight or over dimension applications to improve transport efficiency or to transport indivisible loads usually on specified routes. This paper describes two systems currently in place in Canada and presents a case study to illustrate the technical procedures used.