Discrimination and Estimation of Time-to-Contact for Approaching Traffic Using a Desktop Environment
A. Elizabeth Seward, Daniel H. Ashmead, and Bobby Bodenheimer
Abstract
Each year, thousands of pedestrians are injured or killed in traffic
accidents. Identifying pedestrians' perceptual capabilities for
street crossing decisions is an important problem. This paper
examines this issue by seeking to understand people's
time-to-contact judgments for short-range to long-range
times-to-contact in a desktop environment. Two experiments were
used to test time-to-contact judgments around 4, 7, and 10 seconds.
Both experiments showed subjects videos of a car moving down a road
toward the viewer. The first experiment observed subjects' ability
to discriminate between two different time-to-contact values. The
second experiment measured subjects' absolute time-to-contact
estimates. We found subjects to be accurate at both discriminating
and estimating time-to-contact in a desktop environment. However,
performance worsens at longer time ranges, those that pedestrians
typically use in street-crossing decisions. Our discrimination
thresholds are consistent with other time-to-contact work, and thus
illustrate that desktop environments are plausible settings to use
for time-to-contact studies.
Bobby Bodenheimer 