# Evaluation of Different Work Zone Road-Occupation Schemes for Monorail Construction
## 4 VISSIM Simulation
### Simulation Results  
Due to the different forms of road occupation at intersections affecting the overall traffic operation efficiency, the traffic operation efficiency of intersections with different schemes was evaluated. Usually, the most commonly used indicators for evaluating the operational efficiency of intersections are delay and stop frequency. In addition to both, this study also takes the queue length and the number of vehicles as evaluation indicators. Based on environmental protection considerations, the emission-related parameter CO emissions in VISSIM are considered as one of the evaluation indicators.  
From the indicator results of different schemes in Table 4, it can be seen that there is not much difference in the indicators of the three schemes under the current actual traffic volume situation. However, except for the delay indicator of Scheme 1, which is better than Schemes 2 and 3, all other indicators are not as good as the other two schemes. It can be seen that when the construction work zone occupies the inner lanes of both directions, it is more likely to cause congestion and reduce the traffic efficiency of intersections. On the other hand, there is not much difference in the results of each indicator between Schemes 1 and 3, but Scheme 3 outperforms Scheme 1. This may be due to the fact that although the construction occupation positions are different, the vehicle lanes at the east entrance of the two are the same, affecting only the traffic conditions of the inner lane at the west exit, thus affecting the traffic efficiency of the entire intersection. Scheme 2 has lower delay and stop frequency compared to the other two schemes, while other indicators are better than the other two schemes. Considering the performance of the three schemes under different combinations of traffic volumes, each exhibits its own set of strengths and weaknesses. Therefore, this article conducts a more comprehensive analysis of the three schemes to determine their performance accurately.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Indicator** & **Scheme 1** & **Scheme 2** & **Scheme 3** \\ \hline queue length (m) & 34.03 & 28.24 & 32.61 \\ number of vehicles (veh) & 443 & 460 & 455 \\ Delay (s) & 33.33 & 34.37 & 32.89 \\ Stops Frequency & 0.81 & 0.85 & 0.80 \\ CO emissions (grams) & 702.06 & 654.46 & 669.44 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Simulation results of three schemes.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline  & **Steering** & **Investigated** & **Simulated** & **Single** & **Mean MAPE** \\  & & **(veh/h)** & **(veh/h)** & **MAPE (\%)** & **(\%)** \\ \hline  & straight & 387 & 55 & \(-2.3\%\) & \\ E1 & Left & 97 & 11 & 18.35\% & \\  & right & 54 & 6 & 20\% & \\  & straight & 408 & 58 & \(-2.4\%\) & \\ E2 & Left & 60 & 9 & \(-8\%\) & \\  & right & 132 & 19 & \(-3.6\%\) & \\  & straight & 604 & 78 & 7\% & \\ W & Left & 151 & 17 & 18.9\% & 7.31\% \\  & right & 84 & 11 & 5.7\% & \\  & straight & 549 & 64 & 16.1\% & \\ S & Left & 86 & 12 & 0.5\% & \\  & right & 223 & 33 & \(-6.5\%\) & \\  & straight & 380 & 45 & 14.7\% & \\ N & Left & 88 & 13 & \(-6.4\%\) & \\  & right & 117 & 10 & 38.5\% & \\ \hline \hline \end{tabular}
\end{table}
Table 3: MAPE calculation direction.