## 4 Methodology
### TMR Routing Protocol
Most of the data communications between vehicles should go through the Road-Side Unit (RSU) to control packets transmission and reduce the data traffic in the network. TMR primarily selects the optimum route that has the minimum RTT, and this implies a route that has the least traffic problems such as data congestion and collision. Optimum routes should have RTT that is shorter than a threshold value which is set as the average RTT. This mechanism secures a short route to the RSU. It hence reduces the possibility of having packet loss that may occur with high-speed mobility vehicles getting further away from the RSU. This, in turn, would speed up the transmission of alert messages between vehicles and therefore lessen vehicle accidents. Moreover, TMR reduces the data retransmissions, and this minimizes the data traffic load to deliver the normal messages promptly. The performance of the proposed TMR is assessed by simulations and compared to other protocols. TMR exhibits an increase in the rate of successfully delivered packets over AOMDV, FF-AOMDV, EGSR, QMR, and ISR, respectively. The overall simulation results show that TMR can greatly improve the performance of data communications in VANETs even as the number of vehicles increases. Specifically, TMR can achieve performance enhancement with 5% to 26% overall comparative protocols. In the future, vehicles' density and RSUs distribution on the road should be considered in the data routing methods in VANETs. Conceptualization, all authors; methodology, H.E.-O. ; software, Y.G., N.R.Y. and M.R.M. ; validation, Y.G. and N.R.Y. ; formal analysis, Y.G. and H.E.-O. ; investigation, all authors; resources, Y.G. and N.R.Y. ; data curation, all authors; writing--original draft preparation, all authors; writing--review and editing, Y.G. and H.E.-O. ; visualization, Y.G. and H.E.-O. ; supervision, H.E.-O. ; project administration, H.E.-O. All authors have read and agreed to the published version of the manuscript. This research received no external funding. Not applicable. The authors declare no conflict of interest. ## References

* [PERSON] et al. (2018) [PERSON]; [PERSON]; [PERSON] A survey on recent advances in vehicular network security, trust, and privacy. _IEEE Trans. Intell. Transp. Syst._**2018**, _20_, 760-776. [CrossRef]
* [PERSON] et al. (2020) [PERSON]; [PERSON]; [PERSON]; [PERSON] A p-opportunistic channel access scheme for interference mitigation between v2v and v2i communications. _IEEE Internet Things J._**2020**, \(7\), 3706-3718. [CrossRef]
* [PERSON] et al. (2016) [PERSON]; [PERSON]; [PERSON] Multihop v2i communications: A feasibility study, modeling, and performance analysis. _IEEE Trans. Veh. Technol._**2016**, _66_, 2801-2810. [CrossRef]
* [PERSON] et al. (2016) [PERSON]; [PERSON]; [PERSON] Cadma: Collision-avoidance directional medium access for vehicular ad hoc networks. _Wirel. Netw._**2016**, _22_, 1181-1197. [CrossRef]
* [PERSON] et al. (2019) [PERSON]; [PERSON]; [PERSON] Channel busyness based multipath load balancing routing protocol for ad hoc networks. _IEEE Netw._**2019**, _33_, 118-125. [CrossRef]
* [PERSON] and [PERSON] (2020) [PERSON]; [PERSON] _Routing for Vehicular Ad Hoc Networks_; Springer International Publishing: Cham, Switzerland, 2020; pp. 1243-1245. [CrossRef]
* [PERSON] and [PERSON] (2020) [PERSON]; [PERSON] Multipath routing protocol using genetic algorithm in mobile ad hoc networks. _IEEE Access_**2020**, \(8\), 177534-177548. [CrossRef]
* [PERSON] (2016) [PERSON] Load balancing maximal minimal nodal residual energy ad hoc on-demand multipath distance vector routing protocol (lbmmre-aomdv). _Wirel. Netw._**2016**, _22_, 1355-1363. [CrossRef]* [PERSON] et al. (2016) [PERSON]; [PERSON]; [PERSON]; [PERSON] Advances in vehicular ad-hoc networks (vanets): Challenges and road-map for future development. _Int. J. Autom. Comput._**2016**, _13_, 1-18. [CrossRef]
* [PERSON] et al. (2019) [PERSON]; [PERSON]; [PERSON] [PERSON] Tihoo: An enhanced hybrid routing protocol in vehicular ad-hoc networks. _Eurasip J. Wirel. Commun.