What drives off-road glance durations during multitasking: capacity, practice or strategy?

NHTSA has proposed compliance criteria for in-vehicle tasks in driving simulators. These criteria exclude usage of interfaces with too many long glancing participants. In the current study 30 participants performed three infotainment tasks while driving a high-fidelity driving simulator. Off-road glance durations for three data-trails were analysed to assess the prevalence of long glancers and possible reasons for the existence of long glancers. Results show that 85th percentile off-road glance durations were common, and significantly varied between participants. Also, the number of long glancers was reduced with repetition, but did not change between task types. Furthermore, there was no correlation between drivers' performance on a Trail Making Test and the 85th percentile off-road glance durations. Hence, variations in glance duration seem more to reflect individual glance strategies than in-vehicle task complexity or individual performance capacity measured by the Trail Making Test. The findings in this study have implications for further development of compliance testing procedures. (Paper No. 08-P).