## 4 Results
### Routing Performance Evaluation
#### 4.4.3 Impact of Network Size
When observing the results on the latency variation of routing methods under different network sizes, as shown in Figure 18c, it is clear that the average end-to-end latency for all routing methods increases with the increment of network size. The gradient of increment in latency in the increasing order is the proposed routing, Dijkstra, and AODV. Note that, when the average latency of Dijkstra grew from 9.88 ms to 136.11 ms, the average latency of the proposed routing only grew from 6.64 ms to 106.24 ms when the network size increased from 8 to 256. The proposed method yields low latency due to its mode, which is the highest stable and least delayed mode under low-contention scenarios. The preceding mode results in a significant latency reduction compared to the Dijkstra shortest path algorithm when the network size is large, as evident from Figure 18c. Furthermore, at node size four, the latency of all routing techniques is zero, as no packets are delivered on average by any of the routing methods. Thus, the latency gap between the routing techniques at lower network sizes is low, and the performance gap widens with the increment in network size, as evident from Figure 18c. The reason for the increment in latency with network size is that the average number of hops per route increases with the increment in network size. Thus, when packets are forwarded through a large number of hops, the average latency for routing increases. Furthermore, the low latency of Dijkstra compared to AODV does not make it superior to AODV because Dijkstra has the least PDR, as evident from Figure 18d. On the other hand, the proposed routing method achieves the lowest average latency values while at the same time achieving the highest PDR, which is a remarkable achievement. The results for PDR variation with vehicular network size given in Figure 18d give an insight into the reliability of the routing techniques assessed in this research. As is evident from Figure 18d, the PDR of all routing techniques improves with increasing network size. For smaller network sizes (for example, network sizes of 4 and 8), the PDR gap between the routing techniques is very low, as evident from the overlapping data points and 95% CIs in Figure 18d. In the case of a network of size four, the vehicular network was a network consisting of all nodes being isolated such that the PDR of all routing methods was zero. On the other hand, with the increment in network size, the PDR gap between the routing techniques tends to widen. The increasing order of average PDR for large networks is Dijkstra, AODV, and the proposed routing. However, note that the reliability performance gap between the proposed routing and AODV is slightly wider compared to the PDR gap between AODV and Dijkstra for large networks. Furthermore, for large networks, the lower 95% CI of PDR for proposed routing lies above the upper 95% CI of PDR for AODV, such that the PDR of proposed routing is defensibly better than AODV for large networks under the settings for this experiment. Overall, all communication cost, channel utilization, and latency tend to increase with the increment in network size for the proposed routing, as evident from Figure 18. However, the important thing to note is that average PDR also grows with network size, which compensates for the extra communication costs, channel utilization, and latency that occur in large networks.