Purpose: To determine how accurate normally sighted male and female pedestrians were at making time-to-arrival (TTA) judgments of approaching vehicles when using just their hearing or both their hearing and vision.
Methods: Ten male and 14 female subjects with confirmed normal vision and hearing estimated the TTA of approaching vehicles along an unsignalized street under two sensory conditions: (1) using both habitual vision and hearing and (2) using habitual hearing only. All subjects estimated how long the approaching vehicle would take to reach them (i.e., the TTA). The actual TTA of vehicles was also measured using custom-made sensors. The error in TTA judgments for each subject under each sensory condition was calculated as the difference between the actual and estimated TTA. A secondary timing experiment was also conducted to adjust each subject’s TTA judgments for their “internal metronome.”
Results: Error in TTA judgments changed significantly as a function of both the actual TTA (p < 0.0001) and sensory condition (p < 0.0001). Although no main effect for gender was found (p = 0.19), the way the TTA judgments varied within each sensory condition for each gender was different (p < 0.0001). Females tended to be as accurate under either condition (p ≥ 0.01), with the exception of TTA judgments made when the actual TTA was 2 seconds or less and 8 seconds or longer, during which the vision-and-hearing condition was more accurate (p ≤ 0.002). Males made more accurate TTA judgments under the hearing only condition for actual TTA values 5 seconds or less (p < 0.0001), after which there were no significant differences between the two conditions (p ≥ 0.01).
Conclusions: Our data suggest that males and females use visual and auditory information differently when making TTA judgments. Although the sensory condition did not affect the females’ accuracy in judgments, males initially tended to be more accurate when using their hearing only.