Closed Road Driving Performance: Evidence for a Front Speech Advantage for Older Drivers

Purpose: Previous research using a driving simulator has demonstrated that drivers find it easier to shadow an auditory channel when the information is presented through a speaker positioned directly in front of them, rather than one positioned to their side. The aim of this study was to determine whether this effect is also obtained under more realistic driving conditions where participants drive a vehicle around a closed road course and assess whether older adults, who experience greater difficulties under dual-task conditions, derive similar advantages from changes in speaker position

Methods: The impact of the location of an auditory secondary task on measures of driving performance including the recognition of road signs, detection and avoidance of large low contrast hazards, gap judgment and time to complete the course was obtained for young and older participants as they drove along a closed road driving course. Ten young (Mean age = 26.9 years, SD=4.2) and nine elderly (Mean age = 72.4 years, SD=4.2) participants with normal corrected vision completed the experiment. A composite driving score was also derived to capture the overall driving performance of the individual participants compared to the whole group and included road sign recognition, cone gap perception, course time and the number of road hazards hit; this latter measure was selected rather than including both road hazards seen

Results: The interaction of position and age was marginally significant (p=.07) for the composite Z-score. The composite score indicates that whereas the older adults performed better when the speaker was in the front position, the performance of younger adults worsened. The effect of speaker position on time to complete the road course was marginally significant, (p =.07) with drivers completing the course more quickly when the speaker was mounted on the front position.

Conclusions: The driving measures show that older adults driving performance improved when the direction of spatial visual attention and the location from which the secondary auditory task emanated was congruent.