This paper was presented at the `Cost-Effective Designs for Trucks' session. Long steep downgrades along rural mountainous highways constitute a significant risk to the trucking industry. This paper addresses this risk and suggests practical engineering solutions. The main objective of the paper is to introduce a systematic approach to determine the need for and location of truck escape ramps (TERs). The approach utilizes variables concerning the design vehicle, the road and the driver. These variables are included in either a stochastic or deterministic form. A number of supplementary variables are also used, such as accident history and the presence of objects within the trajectory of a runaway vehicle. The approach also utilizes a number of existing vehicle-road performance models to generate relevant data concerning the descent speed, cornering stability and brake temperature. The application of the methodology is illustrated with examples from highways in mountainous terrain in Jordan and Western Canada. The examples selected are diverse and were chosen to illustrate the generalized nature of the methodology. (A)
Abstract