# Pedestrian Behavior in Static and Dynamic Virtual Road Crossing Experiments
## 4 Discussion  
The capacity to make participants feel that they are actually present in the virtual environment determines the realism of the environment and the usability of the simulator [35]. This will depend on the quality of the graphical representation, sound, and interaction possibilities. This study compares the results of an experimental approach where participants were standing still with another one in which they were asked to walk along a crosswalk. The goal was to assess the impact of the interaction between the participant and the virtual environment on crossing decision-making. Regarding the crossing decisions observed when the vehicle approached the participants at a constant speed, the vehicle speed and initial distance were the most determining variables for the participants' crossing decisions. The percentage of crossings only differed between the two experimental approaches when the vehicle approached at 20 km/h from the initial distance of 35 m, i.e., in the most favorable condition to cross and in which the percentage of crossings was higher. Such as in the static experimental approach, crossing percentages increased with vehicle initial distance in the dynamic method and decreased with its speed. These results confirm again the important role of vehicle speed in crossing decisions when balanced with the distance weight, contrasting with [PERSON] and [PERSON]'s [46] results. Crossing start times were not affected by the initial distance. However, the vehicle speed and the experimental approach had a significant impact on the participants' time to decide to cross. In both experimental approaches, higher speeds have prompted faster decisions. As for the experimental approach's effect, it can be easily explained by the distance of 3 m that participants had to walk after the beginning of the stimuli presentation  
Figure 14: TTP and mean standard error as a function of the experimental approach, per initial speed and speed pattern. and before reaching the curb in the dynamic experiment. Except for one particular condition (a speed of 30 km/h and an initial distance of 25 m), the crossing start times assumed the same trend in both experimental methods. In the dynamic approach, the crossing start times were, on average, 1.58 s higher than in the static experiment. Observations with both experimental approaches showed that a faster-moving vehicle led to less time to decide [47]. Again, the higher speeds and close distances have prompted a similar sense of urgency, accelerating the decision processes. However, this had a repercussion on the accuracy of judgments. In the dynamic experiment, where it was possible to determine the number of crashes, considering the values presented in Table 5, they expressively occurred when vehicle speed was the highest and when the vehicle approached the crosswalk at 20 km/h from the shortest distance. Thus, with both experimental approaches, it was possible to note that the TTP and the crossing start time were directly related when the vehicle approached at a constant speed. Regarding the analysis of the stimuli considering the three different types of speed patterns, the results showed that the initial speed of the vehicle had a significant influence on the percentage of crossings, with the participants crossing more often when the vehicle started at 20 km/h, and on the crossing start time. This is valid particularly for the dynamic experiment, since through the execution of the static experiment, it was verified that the crossing start time (response time) was significantly longer when the vehicle approached the crosswalk at an initial speed of 30 km/h. Participants crossed more when the vehicle varied its speed (slowing down and stopping patterns). In these patterns, most of the static experiment participants and all the participants of the dynamic experiment waited for a speed considerably lower than the initial speed to cross the virtual road. The crossing start time was longer in the dynamic compared to the static experiment.