## 4 Simulation and Practical Application
### Simulation of Typical Form Intersection  
The simulation is conducted on the intersection with integrated waiting area shown in Figure 2. The road segment and intersection model with and without integrated waiting area are respectively established in VISSIM in different scenarios. After that, the corresponding signal control parameters are introduced. One is with integrated waiting areas and the other is without integrated waiting areas. The similar geometric elements are used for intersections with and without integrated waiting areas. The results from the two intersections will be compared so that an overall understanding of the advantages and limitations of integrated waiting areas will be gained.  
The main and pre-signal timing schemes are shown in Tables 2 and 3. Length of the area is set as 70 m, and the average speed in the VISSIM platform for this study is 40 km/h. According to the length of the waiting area and the average speed of the vehicle in the experimental model, the clearing time of the waiting area is considered as 6 s.  
The input of the flow rate of the through, left-turn and right-turn vehicles in the peak hour is 1200 pcu/h, 600 pcu/h and 200 pcu/h respectively. To evaluate the simulation results, the average vehicle delays for an hour with and without the integrated waiting area are calculated and compared as illustrated in Figure 6.  
From the figure, it is observable that the average vehicle delay for left-turn and through movement at a signalized intersection with the integrated waiting area is lower than that without it. However, right-turn vehicles' delay is a little higher. During the simulation, right-turn vehicles only use the rightmost lane in the integrated waiting area and pass through the intersection with the give-way rules. So right-turn vehicles may be delayed by the through vehicles or left-turn vehicles stopping in the front of them. The results indicate that for the general form of the integrated waiting area studied in this paper, the average delay of left-turn vehicles with the integrated waiting area is decreased by about 43%. In addition, the efficiency of the approach in the intersection is increased.  
To evaluate the effect of the design of the integrated waiting areas on the movements at the signalized intersections under different conditions, the volume for the approach is changed. The average vehicle delays for an hour with and without the integrated waiting area under different volumes are calculated and compared as illustrated in Figure 7.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Sequence** & **Phase** & **Green Time (s)** & **Yellow Time (s)** & **Cycle (s)** \\ \hline
**1** & NS Through & 92 & 3 & \\
**2** & WE Through & 30 & 3 & 200 \\
**3** & NS Left-turn & 48 & 3 & \\
**4** & WE Left-turn & 18 & 3 & \\ \hline \hline \end{tabular}
\end{table}
Table 2: Signal timing scheme of the main-signal.  
Figure 6: Comparison of average vehicle delays with and without the integrated waiting area (Note: CON is the conventional intersection without integrated waiting area; IWA is the intersection with an integrated waiting area).  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Sequence** & **Phase** & **Green Time (s)** & **Yellow Time (s)** & **Cycle (s)** \\ \hline
**1** & Through & 107 & 3 & \\
**2** & Left-turn & 75 & 3 & 200 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Signal timing scheme of the pre-signal.