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Simulation Study of the Effect of Four Route Guidance Systems on Driver Distraction


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Suggested Citation:
Srinivasan, Raghavan, Paul P. Jovanis, Chun-Zin Yang, Ryuichi Kitamura, C. M. Hein, Francine H. Landau (1994) Simulation Study of the Effect of Four Route Guidance Systems on Driver Distraction. Institute of Transportation Studies, University of California, Davis, Presentation Series UCD-ITS-RP-94-18

Moving Toward Deployment: Proceedings, IVHS America 1994 Annual Meeting, Atlanta, GA. Vol. 2

A series of realistic experiments have been conducted using a driving simulator developed by Hughes Aircraft Corporation, in order to examine the implications of different types of route guidance systems on driving performance. The focus of the experiments was on en route guidance over predescribed and planned routes. Drivers were asked to follow a predetermined route to the destination. Four types of route guidance systems were tested: (i) Paper Map, (ii) Heads Down Electronic Map, (iii) Heads Up Display (HUD) in combination with Heads Down Electronic Map, and (iv) Voice Guidance in combination with Heads Down Electronic Map.

The experiments were designed so that all subjects were tested using all route guidance systems, using a within subject design. Subjects, recruited by a market research firm, included nine males and nine females.

User perceptions and preferences for the devices and the subjects' subjective assessment of workload were measured using a variety of measuring scales. Reaction times were measured whenever the subject had to react to an external event to avoid a collision. External events included: pedestrians crossing in front of the subject, left turning vehicles, crossing vehicles, obstacles, and changes in traffic signal indication from green to amber. The NASA TLX method was used to measure subjective workload immediately after completing two driving trials with each of the four route guidance systems. Driver preferences of each system were also measured at this time using five dimensions: ease of use, clarity of information, quantity of information, preparation for turns and levels of distraction.

A variety of statistical methods have been applied to the performance measures including analysis of variance, linear regression and logit models. Among the findings are:
  • 1) Subjective workload, user perceptions and number of errors all indicated that the voice guidance/electronic map combination performed the best, and the paper map to be the worst. Somewhat surprisingly, the HUD/electronic map combination performed worse than the electronic map is the case of workload.
  • 2) The reaction time modeling yielded slightly different device performance depending on the event being reacted to. In general, the paper map was associated with largest reaction times.