Using virtual environments to assess time-to-contact judgments from pedestrian viewpoints

Abstract

This paper describes the use of desktop and immersive virtual environments to study judgments that pedestrians make when deciding to cross a street. In particular, we assess the ability of people to discriminate and estimate time-to-contact (TTC) for approaching vehicles under a variety of conditions. Four experiments observing TTC judgments under various conditions are described. We examine the effect of type of vehicle, viewpoint, presentation mode, and TTC value on TTC judgments. We find no significant effect of type of vehicle or of viewpoint, extending prior work to cover all views typically encountered by pedestrians. Discrimination of short values for TTC judgments is generally consistent with the literature, but performance degrades significantly for long TTC values. Finally, we find no significant difference between judgments made in a desktop environment versus a head-mounted display, indicating that tracking the approaching vehicle with one's head does not aid discrimination. In general, people appear to use strategies similar to those that pedestrians use to make real-world, street-crossing decisions.

How Do Vision and Hearing Impact Pedestrian Time-to-Arrival Judgments?

“…We found that the accuracy of TTA judgments decreased with increasing TTA. These results agree with the laboratory based results of Schiff and Detwiler, 9 Schiff and Oldak, 7 and Seward et al 11 …”

“…Having subjects make instantaneous TTA decisions about approaching vehicles is however more realistic to the actual task of crossing the street than waiting to make the decision until the car reaches the judgment point. Interestingly, when Seward et al 11 used an immersive virtual environment, which may be considered to be more realistic to the real-world than films used in the laboratory based experiments, they found that subjects on average overestimated the TTA by 0.77 seconds, which was similar to our results. Thus it is possible that there is a tendency to have less overall error in making TTA judgments when assessing performance in a more realistic environment as opposed to testing performance using two-dimensional films.…”

“…6 seconds or less) or for only a few selected TTA values—often just assessing performance for only 3–4 TTA categories. 6–8,11 Assessing performance over a broad range of TTA values is important because most real-world street-crossing situations require pedestrians to make decisions based on much longer TTA values.…”

“…Based on the results of previous studies, we hypothesized that the female subjects would not perform as well as the male subjects, TTA judgments would become less accurate with increasing TTA, and subjects would perform better under the vision and hearing condition than the hearing only condition. 6,7,10,11 …”

Bimodal task-facilitation in a virtual traffic scenario through spatialized sound rendering

“…For instance , Te Velde et al [2005] simulated traffic environments with artificial indoor streets, or Sidaway et al [1990] and Tung et al [2008] used prerecorded road environment videos in their experiments. However, VEs and virtual reality technology have emerged as the preferred tool to simulate interactive traffic environments (e.g., Simpson et al [2003]; Seward et al [2007]). Since safety-training can effectively improve pedestrian traffic safety [Barton et al 2007], but reasonable real-world environments for traffic safety training are expensive and difficult to realize, computer generated VEs also found great reception for safety-training simulators [Oxley et al 2008;Cavallo et al 2009;Schwebel and McClure 2010].…”