Comparison of alternative methods for presenting trip navigational information to motorists.

Throughout the world there are more than 50 modern directional guidance systems under development, including major components of the Japanese AMTICS program, the European PROMETHEUS project and the North American IVHS program. A study of nine road navigation techniques was conducted using a part-task simulator. Experimental treatments were defined by two dimensions: presentation mode (map, list or auditory display) and operator memory requirement (short term, long term or mixed). Seventy four subjects, ranging from 18 to 79 years, participated in the study. Males comprised 59.4 percent of the sample. Subjects participated in scenarios which simulated both short (four intersections) and long (20 intersection) trips. Subjects made turning decisions, performed a signal detection task throughout the entire scenario and answered questions about landmarks they had passed or which they might encounter during a future portion of the simulated trip. Navigation performance measures included choice response times to street signs at intersections, the proportion of correct turn decisions, signal detection (tracking) reaction times and the proportion of signals detected while the intersection and street sign were visible. Orientation performance responses included: the percent correct answers to the relative location of landmarks, response time to the landmark questions, and signal detection rates during the period when landmarks were visible. Navigation and orientation performances obtained from subjects in each of the nine experimental treatments were compared to performances of test subjects in a control group where no navigational or orientation information was explicitly presented. Measures of map reading skill were correlated with navigational performance. Landmark usage, trip planning techniques and recovery strategies employed when drivers were lost were compared for young, middle age and elderly drivers comprising the test sample. Results of this study are compared with other laboratory and field tests of navigational performance which have employed some of the techniques included in this study. Additional research needs and future human factors analyses are identified. Implications for the design of in-vehicle information system displays are given.