# A Method for the Rapid Propagation of Emergency Event Notifications in a Long Vehicle Convoy
## 5 Results
### General Trends and Analysis  
The Convoy VANET system generally works well at ensuring a quick propagation of SMs. The standard spacing scenarios consistently show less than 20 ms propagation times to the end of the convoy, even with a doubled delay and delay randomness (Figures 1, 3 and 5). All but the far-spacing plus doubled-delay situation (Figure 15) consistently resulted in propagation times lower than 0.10 s to the end of the convoy. The reception delay generally follows a linear trend outside the close-spacing situations (Figures 7, 9 and 11), and the number of SM transmissions are mostly consistent across the convoy (barring nodes 0 and 19 of course). The number of SM transmissions is typically reasonable given the channel reliability as well. For a 65% reliability link (i.e., a 60 m distance), it would require, on average, approximately 1.54 transmissions before the first successful reception. This means that there would be an average of approximately three transmissions for a successful single message exchange between two nodes. We see for the far-spacing situation that most of the nodes transmit between one and five times per safety event (see Figures 13, 15 and 17). The 3D bar plots show that for each safety event, there is a small subset of nodes that transmit much more than the others (e.g., Figures 2, 4 and 6). However, this subset typically changes for each safety event, leading to the bar and whisker plots showing an even distribution of high-transmission outliers (e.g., Figures 14, 16 and 18). Doubled delays tend to increase the reception delay while having a minimal effect on the number of transmissions. Doubled-delay randomness tends to not increase the reception delay at all over standard delays, while also not having a significant effect on the number of transmissions. The most significant factor in the number of transmissions and reception delay is spacing, which it is effectively a proxy for communication reliability. Close spacing results in many nodes receiving the first transmission, as seen by how the reception delays only increase marginally for the rearward nodes. Far spacing results in a wider variance of propagation delay as most receptions occur between immediate neighbors, leading to more opportunities for delays. The \"far-to-close\" spacing tests produce results that resemble a combination of all three fixed spacing tests. The reception delay plots in Figures 19, 22 and 25 show the higher-end tracking more closely to the far spacing tests and the lower-end tracking more closely to the standard- and close-spacing tests. The number of transmissions do not change much over the course of the vehicle movement, apart from the very last SM event at the closest distance having several non-transmitting nodes (Figures 20, 23 and 26). Of particular importance are Figures 21, 24 and 27. These figures illustrate the data contained in the reception delay plots in Figures 19, 22 and 25, respectively, but are here separated by SM events. They were included to show how the reception delay for each vehicle decreases as they move closer together. This highlights the Convoy VANET system's ability to adapt to changing scenarios, taking advantage of a more reliable communication channel to reduce propagation delay.