Project-Level Highway Management Model for Secondary Highways in Saskatchewan, Canada

摘要

Saskatchewan Highways and Transportation (SHT) is responsible for 26,000 km of primary and secondary highways in the province. The primary system was structurally built to handle high traffic volumes and heavily loaded trucks; the secondary system was constructed to provide links into the primary system for traffic volumes lower than 500 vehicles per day with few heavily loaded trucks. Secondary highways consist mostly of thin membrane surface (TMS) highways, which are oil-treated surfaces over a nonstructural roadbed. In the past few years increased heavy-truck traffic associated with rail line abandonment, elevator closures, and increased truck haul associated with economic development has deteriorated TMS highways. Years of increasing pressures and inadequate funding have forced SHT to develop and implement cost-effective, sustainable methods to manage and preserve them. A new strategy to structurally strengthen the system is a cementitious blend of material called TerraCem. Along with conventional strengthening strategies, this new method is being used throughout Saskatchewan; however, its long-term performance is unknown. Because SHT must make good decisions and should be able to demonstrate they are good, a project-level framework capable of evaluating secondary road management strategies on the basis of whole life-cycle road agency and road user costs, has been developed. The framework determines the lowest-cost strategy (agency and road user) and employs probabilistic modeling to quantify the long-term performance of the TerraCem strategy. The developed framework was applied for a project-level sample.