Turn-by-Turn Displays Versus Electronic Maps:
An On-the-Road Comparison of Driver Glance Behavior
(UMTRI-98-37)

Aaron Brooks, Christopher Nowakowski, and Paul Green

January, 1999

This report is the fifth in a series that examines the use of electronic navigation displays while driving. Sixteen subjects (ages 18 to 30 and 65+) drove a test vehicle on freeways, city streets, and residential streets to six specified destinations in a fixed order. The vehicle was equipped with two Magellan PathMaster navigation units which bracketed the steering wheel, one showing turn-by-turn guidance and one showing a route map. Glances to each display were examined.

The average number of glances per subject was 291. Over the 30.7-mile route, each subject averaged 9.5 total glances per mile. Overall, the turn-by-turn display was looked at 3.75 times more often than the route map display, with a higher ratio when the turn-by-turn display was on the right side of the steering wheel than when it was on the left.

For the turn-by-turn display, a burst of glances usually occurred at the beginning of the segment followed by a lower steady rate for the rest of the segment. Glances to the route map display were relatively uniform throughout each of the segments. Also, glance bursts usually occurred when the navigation systems beeped or spoke.

The glance rate (total glances per mile per subject) decreased as segment length increased and was much higher for city segments than for freeway segments (10.8 and 6.9 glances per mile per subject, respectively).

Graphical Abstract (.pdf) | UMTRI-98-37 Full Report (.pdf)

 

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