## 3 Results and Discussions
### Route Validity Time
The limited variation in PDR observed for AODV can be attributed to its reactive routing mechanism, which establishes routes on demand. AODV's performance remains relatively stable across different route validity times, indicating that it effectively maintains packet delivery regardless of how long routing information is retained. This consistency is significant in both city and highway environments, where AODV's ability to promptly initiate route discovery can mitigate the effects of fluctuating network conditions. However, the marginal increase in PDR with longer route validity times suggests that, while AODV benefits from fresh route information, it does not significantly leverage extended validity to enhance packet delivery performance. In contrast, GPSR's trend of increasing PDR with longer route validity times underscores its operational advantages in both environments. As route validity time increases, the protocol is less burdened by the overhead associated with frequent route discoveries. This reduction in overhead allows GPSR to allocate more bandwidth for data transmission, thereby improving the chances of successful packet delivery. The implications are particularly pronounced in city environments, where node density is higher, and maintaining stable routes is crucial for optimizing communication efficiency. The higher PDR observed with longer validity times highlights GPSR's capacity to effectively utilize the network's resources by minimizing the disruption caused by route recalculations. The ability of GPSR to maintain higher PDR with extended route validity is also linked to its greedy forwarding strategy, which capitalizes on the spatial density of nodes. In urban settings, where vehicles are frequently in proximity, longer route validity times enable the protocol to exploit stable connections, reducing the likelihood of packet loss due to route changes. This is particularly relevant in high-mobility scenarios, such as highways, where maintaining a consistent route is essential for maximizing data throughput and reliability. Overall, the findings presented in Figure 11 highlight the distinct operational characteristics of AODV and GPSR in terms of PDR as they relate to route validity times. While AODV maintains a stable PDR across varying validity periods, GPSR benefits significantly from longer route validity times, leading to improved packet delivery outcomes. This analysis underscores the importance of selecting appropriate route validity parameters tailored to the specific routing protocols and environmental contexts to optimize overall network performance. Figure 11: PDR comparison between VANET scenarios and route validity time. This study, based on VANET and VANET technology, appears to be a promising solution for human transportation systems. It provides a wide range of applications, including safety, traffic information, and infotainment [25]. VANET started to attract the attention of industry, government, and research organizations. The special characteristics and features of VANET make it different than its successor, MANET. Just to list a few: the mobility of nodes, scalability, and the multi-scenario phenomenon. These characteristics bring challenging tasks in the design and development of VANET protocols and standards, including routing, medium access control, and application management [26]. As explained earlier, the work focused on the design of a routing protocol to handle these characteristics and features. Specifically, the dynamic topology changes and the multi-scenario phenomenon in VANET. Accordingly, a chameleon method (CM-routing) is developed and integrated with AODV (CM-AODV) and GPSR (CM-GPSR) routing protocols. CM method mimics the adaptation behavior of the Chameleon lizard. Chameleon Lizard changes its skin color to match the surrounding environment. This helps the lizard hide and hunt.