Highway geometric design changes in response to a fully autonomous vehicle fleet. (c2018)

Abstract

This research investigates the potential changes in the geometric design of highway elements in response to a fully autonomous vehicle fleet. When driverless vehicles completely replace conventional vehicles, the human driver will no longer be a concern. Currently, and for safety reasons, the human driver plays an inherent role in designing highway elements, which depend on the driver’s perception-reaction time (PRT), driver’s eye height and other driver parameters. This study focuses on the geometric design elements that will directly be affected by the replacement of the human driver with fully autonomous vehicles. Stopping Sight Distance (SSD), Decision Sight Distance (DSD), and length of sag and crest vertical curves are geometric design elements directly affected by the inevitable change. Revised formulations for such design elements are presented herein. The effects of the proposed revised formulations are quantified using a real-life scenario. An existing real-life roadway designed using current AASHTO standards has been redesigned with the revised formulations. Compared with the existing design, the new design shows significant economic and environmental improvements, given the elimination of the human driver from autonomous vehicles.