## 8 Conclusions  
The rapid construction of freeways, especially the expansion of the around-city freeway, inevitably produces more and more compound interchanges. The complex weaving behavior of compound interchanges seriously impacts traffic efficiency and safety. However, compound interchanges in China have various auxiliary lane forms, and the lack of specific standards for selecting the appropriate forms has led to some design problems regarding efficiency, safety, and land utilization. In this study, four auxiliary lane design forms were proposed for compound interchanges, which were simulated via VISSIM traffic simulation software based on measured data. To comprehensively assess the reliability of the four schemes in terms of traffic efficiency, safety, and environmental protection, several evaluation indexes were selected, \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & \begin{tabular}{c} **The Number** \\ **of Conflicts** \\ \end{tabular} & **TTC** & **PET** & **CSI** & \begin{tabular}{c} **Travel** \\ **Time** \\ \end{tabular} & **Delay** & \
\begin{tabular}{c} **CO** \\ **Emissions** \\ \end{tabular} &
\begin{tabular}{c} **Fuel** \\ **Consumption** \\ \end{tabular} \\ \hline
1 & 62 & 0.36 & 0.35 & 0.24 & 77.81 & 2.58 & 5967.36 & 85.39 \\
2 & 38 & 0.23 & 0.31 & 0.17 & 84.2 & 4.73 & 5350.25 & 76.54 \\
3 & 48 & 0.24 & 0.32 & 0.20 & 70.96 & 1.3 & 4948.78 & 70.78 \\
4 & 183 & 0.15 & 0.03 & 0.27 & 74.86 & 1.44 & 5019.78 & 71.78 \\ \hline \hline \end{tabular}
\end{table} 
Table 23: Simulation results with measured traffic volume. using the FAM to downsize the indexes and combine them with the EWM for comprehensive weighting to accurately, intuitively, and efficiently select the appropriate design scheme. The proposed auxiliary lane form can be widely used in small spacing interchanges under different traffic conditions and transformed into a compound interchange. This implementation aimed to enhance traffic efficiency, improve driving safety, and promote environmental protection capability. The conclusions obtained in this study can be summarized as follows. 1. The auxiliary lanes of Scheme 1 were most effective under specific traffic conditions. When the traffic volume was less than 3960 veh/h, the diverging-emerging ratio was higher than 40%; when the traffic volume exceeded 3960 veh/h, the diverging-emerging ratio was 10-20%. However, in practice, the score gap between Schemes 1 and 2 is so small that they can be substituted for each other at low traffic volumes and low diverging-emerging ratios;
2. Scheme 2 had the most advantages under low traffic volume and diverging-emerging ratio. Specifically, when the traffic volume is below 3960 veh/h and the diverging-emerging ratio is 10-40%, opting for Scheme 2 as the auxiliary lane form is recommended. This scheme proved to be adaptable and suitable for a wide range of traffic situations. In addition, its unique design can save much land and has good adaptability in terrain-restricted areas;
3. When the traffic volume surpasses 3960 veh/h, and the diverging-emerging ratio exceeds 20%, it is advisable to select Scheme 3 as the preferred auxiliary lane form;
4. The Scheme 4 B-type weaving area has the worst safety. This design leads to the inner ramp vehicles emerging directly into the mainline, interfering with straight vehicles and generating many conflicts. The more vehicles in the inner lanes of the ramp, the more serious the interference;
5. The environmental impact of different types of auxiliary lanes varies greatly, up to 81.05%. A reasonable choice of auxiliary lane form is conducive to improving the environment. The proposed design forms for continuous auxiliary lanes in this article demonstrate good applicability. They can be applied to newly constructed and existing freeways to ensure economic efficiency and space-saving.