On-the-Road Tests of Driver Interfaces:
Examination of a Route Guidance System and a Car Phone

Paul Green, Eileen Hoekstra, and Marie Williams

November, 1993

In this experiment 8 drivers (4 younger, 4 older) drove a 19 turn, 35-minute route. The route included sections through residential neighborhoods, on city streets, and on expressways. They were guided by an experimental navigation system that provided turn-by-turn instructions via a display mounted on the instrument panel. During the trip each driver was asked to dial six phone numbers and participate in simulated phone conversations. At the end of the trip drivers were asked to rate the difficulty of a variety of driver-information-system-related tasks.

The instrumented car recorded lateral position in the lane, speed, throttle position, steering wheel angle, eye fixation location, and other measures. Typical lateral standard deviations were 0.5 feet and decreased with speed. Speed standard deviations were slightly in excess of 1 mile per hour. Using the phone and navigation systems resulted in slight increases in the standard deviation of throttle position and the standard deviation of steering wheel angle.

There were 8 navigation errors made by the 8 drivers in this experiment, comparable to the 25 errors from 30 drivers in a previous experiment. This experiment demonstrated that repeatable and reliable measures of driver performance and behavior could be obtained using the test protocol employed in this experiment

UMTRI-93-35 Full Report (.pdf)


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