Human Factors Considerations for Automotive Navigation Systems-- Legibility, Comprehension, and Voice Guidance
Kenji Kimura Kenji Marunaka Seiichi Sugiura Toyota Motor Corporation, Aichi, Japan
An in-vehicle navigation system provides current and local area road information and route guidance to a destination. This can reduce driver stress and improve route efficiency, thereby contributing to safe and economic driving. Providing road information and route guidance is complicated by the fact that the driver's attention is divided between many simultaneous tasks: visual scanning of navigation system display/controls, motor and visual tasks involved with primary vehicle controls (steering, pedal, controls, turn signals), and visual road and traffic information perception in the direct and indirect field of view. Accordingly, the human interface of a navigation system must be developed so that the driver may perceive guidance information as unobtrusively as possible while driving.
Zwahlen, Adams, and Debald ( 1988) proposed that a 1-2 sec average duration per look at car displays or controls is the guide to be used when designing sophisticated in-vehicle displays, or CRT touch panel controls and/or applications. Wierwille, Antin, Dingus, and Hulse ( 1988) investigated glance time for drivers to observe and operate in-vehicle displays and controls (conventional and navigation systems).
In order to ensure that the driver can assimilate route guidance information from the navigation system within the available glance time, character size, color combinations of display characters, map display, and amount of route information should be considered. There are a few studies on the legibility and comprehension of displayed information in the field of automotive navigation systems. Shekhar, Coyle, Shargal, and Kozak ( 1991)