Determining Need for and Location of Truck Escape RAMPS

Abstract

The main objective of this 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. Vehicle variables include vehicle type, gross vehicle weight, and brake type. Road variables include the profile (length and steepness of grade), horizontal curvature (cornering speed), and the availability of a brake-check area at the top of the grade. Driver variables include information about the driver's actions at the brake-check area, brake checking, and gear selection. A number of supplementary variables are also included, such as accident history and the presence of objects in the path 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 of Jordan and western Canada. The examples selected are diverse and were chosen to illustrate the generalized nature of the methodology.