Christopher Nowakowski and Paul Green
Recent concern has been expressed over the use of cell phones and navigation systems while driving. Several efforts, including SAE Recommended Practice J2364 ("the 15-second rule") and J2365 (the associated calculation procedure), have recently tried to provide guidelines for the design of in-vehicle devices. The purpose of this study was to examine a destination selection task in the model year 2000 Nissan Infiniti I30 navigation system (which was allowed while driving) in the context of SAE J2364 and J2365.
Eight licensed drivers between the ages of 20 and 30 (mean of 25 years old) selected destinations using the in-vehicle navigation systemıs address book and nearby points of interest features. The tasks were performed both while the vehicle was parked and while driving on a 2-lane expressway during low-volume traffic conditions at 70 mph.
The mean measured task time while the vehicle was parked was 13.20 seconds, requiring an average of 8.8 keystrokes to complete the task. The mean measured-task time while driving on the expressway was 15.85 seconds or approximately 1.2 times the measured task time while parked.
Subtracting system delays greater than 1.5 seconds, the mean keying time was 6.13 seconds when the vehicle was parked. Consequently, given that SAE J2364 specifies testing older drivers who typically take up to 1.8 time longer to complete in-vehicle tasks, a task of 11 keystrokes or less would pass the "15-second rule." SAE J2365 was also used to estimated the task times while the vehicle was parked, and it was found to slightly overestimate the task times by a mean of 0.68 seconds.
|Graphical Abstract (.pdf)|||||UMTRI-2000-49 Full Report (.pdf)|
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