## 5 Results and Discussion
### Comparison of Fairness  
During the experimentation outlined in Section 5.1, aside from collating data pertaining to the average travel delay and average fuel consumption of CAVs, we also amassed fairness metrics for the four strategies. These metrics have been delineated in Table 2 and graphically depicted in Figure 10.  
Figure 9: Acceleration (**a**) and fuel consumption rate (**b**) for a CAV encountering red lights.  
In line with the findings from the analysis of driving performance, under scenarios of moderate to low traffic demands, cooperative driving strategies also demonstrate significant enhancements in fairness compared to the traffic light strategy. However, unlike in the evaluation of driving performance, both the DRP and LDR strategies marginally trail behind the FIFO strategy in terms of fairness. This discrepancy primarily stems from the inclination of resequencing strategies to prioritize non-conflicting CAVs with lower collision avoidance costs for intersection passage. While conflicts among CAVs on the same or opposing lanes remain minor, congestion tends to dissipate more readily but may exacerbate in other lanes. Furthermore, the DRP strategy, through the incorporation of platooning algorithms, exhibits a greater propensity to prioritize CAV passage on the same or opposing lanes. In the assessment of cooperative driving strategies, its fairness performance ranks third. However, it is important to note that across five different traffic  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Arrival Rates (veh/h/lane)** & **Driving Strategies** & **Fairness Indicator \(\rho\) (s)** \\ \hline \multirow{4}{*}{160} & Traffic light & 18.50 \\  & FIFO & 2.38 \\  & LDR & 3.12 \\  & DRP & 3.16 \\ \hline \multirow{4}{*}{320} & Traffic light & 20.28 \\  & FIFO & 2.61 \\  & LDR & 3.01 \\  & DRP & 3.16 \\ \hline \multirow{4}{*}{480} & Traffic light & 20.48 \\  & FIFO & 1.71 \\  & LDR & 2.72 \\  & DRP & 2.74 \\ \hline \multirow{4}{*}{640} & Traffic light & 21.00 \\  & FIFO & 5.03 \\  & LDR & 6.76 \\  & DRP & 8.26 \\ \hline \multirow{4}{*}{800} & Traffic light & 21.48 \\  & FIFO & 18.15 \\ \cline{1-1}  & LDR & 10.88 \\ \cline{1-1}  & DRP & 12.33 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Data on the fairness indicator of different driving strategies under different arrival rates.  
Figure 10: The fairness indicator of different driving strategies under different arrival rates.  
demands, the fairness indicator of the DRP strategy trails the top-ranked strategy by only 0.72 s, 0.49 s, 1.03 s, 3.23 s, and 1.35 s, respectively. In Table 1, under the same five traffic demands, the DRP strategy surpasses these strategies by reducing the time by 2.17 s, 2.32 s, 2.61 s, 3.53 s, and 2.14 s, respectively. This suggests that, when considering both overall driving performance and fairness, the DRP strategy maintains an advantage over other strategies.  
It is noteworthy that, under higher traffic demands, the fairness performance of the LDR and DRP strategies surpasses that of the FIFO strategy. To delve deeper into this phenomenon, we conducted a detailed analysis and visualized the comparison of trip durations for 90 CAVs under the FIFO, LDR, and DRP strategies when the arrival rate is 800 veh/h/lane in Figure 11. From the graph, it is evident that, under the FIFO strategy, the trip duration for CAVs after ID 61 exceeds 70 s, with some even reaching up to 100 s. This accumulation occurs due to the substantial buildup of CAVs within the intersection, highlighting the inefficiency of the FIFO strategy in coordinating CAVs' departure from the intersection, resulting in severe traffic congestion. In contrast, the trip durations of CAVs under the LDR and DRP strategies remain within 60 s. This indicates that enhancing the traffic coordination capability of strategies to mitigate traffic congestion may not necessarily conflict with improving fairness, particularly under high traffic demands.