# Behavioral Dynamics of Pedestrians Crossing between Two Moving Vehicles
## 3 Results
### Behavioral Response to Gap Features  
Restricting the analysis to simple crossings, we consider the variations of the parameters to changing crossing conditions. Experimental parameters \(y_{0}\) and \(l_{g}\) affect directly the affordance of the gap by changing the temporal window of the gap or the distance the pedestrian needs to traverse to reach the gap. Effects of the experimental parameters on the three fitting parameters \(v_{\max}\), \(t_{a}\), and \(\tau\) have been examined; only \(t_{a}\) has turned out to respond significantly. Figure 4 shows the distribution of \(t_{a}\) obtained for several values of \(y_{0}\) and \(l_{g}\). It is observed that \(t_{a}\) generally increases as \(y_{0}\) approaches zero. This can be understood intuitively as follows: Recall that \(y_{0}\) denotes the distance the pedestrian must traverse to reach the gap. The larger the distance, the earlier they must begin walking. However, when the initial position is farther, namely, when \(y_{0}\) is made larger, this trend disappears and \(t_{a}\) tends to stay at slightly over one second (\(t_{a}\ \gtrsim 1\,s\)). This is likely to result from the minimum response time. Namely, the pedestrian may not cross earlier than the earliest timing at which they can reasonably begin to walk. On the other hand, an increase in the gap size appears to lower \(t_{a}\). This indicates that, when the gap is accessible earlier, the pedestrian tends to cross earlier. The distributions of the other two parameters \(v_{\max}\) and \(\tau\) have also been examined. While the average value of \(v_{\max}\) tends generally to increase with \(y_{0}\), the trend is not statistically significant. No significant trends have been observed for \(\tau\). Contrary to \(y_{0}\) and \(l_{g}\), the vehicle speed \(v_{c}\) and the vehicle type are manipulated without changing the gap affordance. These experimental parameters affect the visual perception of the gap without changing its temporal window of availability. Figure 5 displays the effects of the vehicle speed and type on \(t_{a}\) when the gap time \(t_{g}\) is set to be 3 s and \(y_{0}\) to be \(-3.5\) m. Doubling the vehicle speed results \begin{table}
\begin{tabular}{c c c c} \hline \hline \multicolumn{3}{c}{**Successful Crossings**} \\ \hline \(y_{0}\) **(m)**\(l_{g}\) **(m)** & **20.8** & **25** & **33.3** \\ \hline \(-3.5\) & 88 \% & 100 \% & 100 \% \\ \hline \(-4.5\) & 100 \% & 100 \% & 100 \% \\ \hline \(-5.5\) & 100 \% & 94 \% & 100 \% \\ \hline \(-6.5\) & 82 \% & 94 \% & 100 \% \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Proportion of successful crossings to all crossing attempts for several values of \(y_{0}\) and \(l_{g}\), when \(v_{c}=30\) km/h and vehicle type is sedan. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multicolumn{3}{c}{**Two-Step Crossings**} \\ \hline \(y_{0}\) **(m)**\(l_{g}\) **(m)** & **20.8** & **25** & **33.3** \\ \hline \(-3.5\) & 42 \% & 25 \% & 6 \% \\ \hline \(-4.5\) & 31 \% & 0 \% & 0 \% \\ \hline \(-5.5\) & 0 \% & 26 \% & 0 \% \\ \hline \(-6.5\) & 15 \% & 6 \% & 0 \% \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Proportion of two-step crossings to all successful crossings for several values of \(y_{0}\) and \(l_{g}\), when \(v_{c}=30\) km/h and vehicle type is sedan. in a significant increase in \(t_{a}\). Moreover, in several cases, buses resulted in a greater value of \(t_{a}\) than sedans did. On the other hand, when the same comparison is made for data with \(y_{0}<-3.5\,\)m, there arises no significant shift in \(t_{a}\) or \(t_{d}\) upon changing the vehicle type. For \(y_{0}<-4.5\,\)m, no significant shift is observed upon changing the vehicle speed as well. This suggests that, when the initial distance is sufficiently far, pedestrian's judgement of the gap is hardly affected by the vehicle type or speed. Finally, we examine differences among age groups.