Purpose
To examine the effects of
optical blur, auditory
distractors, and age on eye movement patterns while performing a
driving hazard perception test (HPT).
Methods
Twenty young (mean age 27.1 ± 4.6 years) and 20 older (73.3 ± 5.7 years) drivers with normal vision completed a HPT in a repeated-measures counterbalanced design while their
eye movements were recorded. Testing was performed under two visual (best-corrected vision and with +2.00DS blur) and two distractor (with and without auditory distraction) conditions. Participants were required to respond to road hazards appearing in the HPT videos of real-world
driving scenes and their hazard response times were recorded.
Results
Blur and
distractors each significantly delayed hazard response time by 0.42 and 0.76 s, respectively (p < 0.05). A significant interaction between age and
distractors indicated that older drivers were more affected by
distractors than young drivers (response with
distractors delayed by 0.96 and 0.60 s, respectively). There were no other two- or three-way interaction effects on response time. With blur, for example, both groups fixated significantly longer on hazards before responding compared to best-corrected vision. In the presence of
distractors, both groups exhibited delayed first fixation on the hazards and spent less time fixating on the hazards. There were also significant differences in eye movement characteristics between groups, where older drivers exhibited smaller saccades, delayed first fixation on hazards, and shorter fixation duration on hazards compared to the young drivers.
Conclusions
Collectively, the findings of delayed hazard response times and alterations in eye movement patterns with blur and
distractors provide further evidence that visual impairment and
distractors are independently detrimental to
driving safety given that delayed hazard response times are linked to increased crash risk.
