Steep road grades provide managers with a way to reduce the economic and environmental costs of transportation systems. Available formulas for calculating log truck gradeability do not consider the performance of log trucks on horizontal curves. The maximum grade thata log truck can climb on a circular curve is less than that on a tangent for a number of reasons. These factors are discussed and some preliminary results obtained from a mathematical model are presented. Predictions from the mathematical model are compared with field observations collected from a survey of steep road operations from forest road managers throughout the usda forest service. This paper appears in transportation research record no. 1291, Fifth internationalconference on low-volume roads, may 19-23, 1991, raleigh, north carolina, volume 2.
Abstract