Issues Related to the Use and Design of a Backing Rear Cross Traffic Alert System

Alternative implementations of a Rear Cross Traffic Alert (RCTA) system intended to actively notify drivers of the presence of rear cross-path traffic when backing were evaluated in naturalistic settings. The feature is one of several emerging technologies designed to assist drivers when backing in this case, enhancing drivers' awareness of traffic approaching from the rear. The study allowed performance under a range of RCTA system driver interface implementations to be contrasted with conventional and wide Field of View (FOV) Rear Vision systems. Evaluations were conducted using a sample of 70 drivers under naturalistic settings and environments with repeated exposures to backing tasks. The study also made use of a staged conflict situation with a confederate vehicle in order to more precisely quantify driver behavior and system usage across drivers under controlled conflict situations. Contrasts among the experimental configurations allowed for comparisons across the major system design factors, including the use and location of visual warnings, auditory alerts, and Rear Vision system FOV. Results found that use of RCTA systems, which include an audible warning component and Rear Vision screen, reduced backing encroachments into the path of approaching traffic by up to 44%, and enabled drivers to respond faster to the presence of cross traffic as compared to Rear Vision Only systems. Although drivers in this study preferred implementations with a wide camera FOV (180degree span), related work in this area suggests that preference for camera FOV may be dependent on driver task and functions (e.g., parking, extended backing, trailer hitching, etc). INTRODUCTION This study investigated performance benefits and driver behavior associated with the use of an Active Rear Cross Traffic Alert (RCTA) system intended to notify drivers of the presence of rear cross-path traffic when backing. This feature is one of several emerging technologies designed to assist drivers when backing in this case, enhancing drivers' awareness of traffic approaching from the rear. The system's longer and wider sensing range and active alerting function potentially offers enhanced detection performance over conventional rear vision systems in situations where cross traffic is present. While all conditions included Rear Vision, driver performance with Active RCTA variants (i.e., those with audible and visual overlay or icon alerting components) was characterized and compared to performance with Rear Vision Only variants (“Passive” RCTA). In addition, both wide (180°) and regular (130°) Field of View (FOV) rear vision system combinations were considered, amongst other system variations. The study recruited 70 drivers, each of whom were exposed to one of the RCTA system combinations, depending upon the experimental condition. The study made use of a staged conflict situation with a confederate vehicle in order to quantify driver behavior and system usage under controlled conflict situations. Evaluations were also conducted using naturalistic settings and environments (e.g., shopping center and mall parking lots, etc.) with repeated exposures to backing tasks, allowing opportunities to capture naturally occurring events. Issues Related to the Use and Design of a Backing Rear Cross Traffic Alert System 2011-01-0578 Published 04/12/2011 M. Lucas Neurauter and Robert E. Llaneras Virginia Polytechnic Inst. & State Univ. Brian Li and Charles Green General Motors Company Copyright © 2011 SAE International doi:10.4271/2011-01-0578 Gratis copy for Michael Neurauter Copyright 2011 SAE International E-mailing, copying and internet posting are prohibited Downloaded Friday, March 25, 2011 08:55:48 AM