## 8 Findings and Conclusions  
The research presented in this paper studied the impact of C-V2X communication technology on the performance of an Energy-Efficient Dynamic Routing application. We leveraged a communication dataset produced from the industry to model the C-V2X communication system. The data were used to calibrate a general function that produces the Packet Reception Ratio (PRR) given the distance between the transmitting and receiving vehicles and the vehicle density in the vicinity of the receiving vehicle within the communication range. We incorporated the communication model in the INTEGRATION microscopic traffic simulator, which supports large-scale traffic simulations. The existing IDEAL Connected Energy-Efficient Dynamic Routing (C-EEDR) application was modified to incorporate our C-V2X model and account for the C-V2X communication constraints (mainly packet losses). The C-EEDR application was evaluated using the IDEAL communication setting (default implementation without packet loss) and using the C-V2X communication model. The simulations were run on the Los Angeles (LA) downtown large-scale road network considering four traffic demand levels and nine market penetration rates. We also compared the performance of the C-EEDR application to the base case where the application is not enabled. The base case used the Frank-Wolf user equilibrium method for routing the vehicles in the road network. The simulation results demonstrated that the C-V2X-based C-EEDR application followed the same behavior as the IDEAL-based C-EEDR application with a slight decrease in benefits. The results demonstrate that the C-EEDR application achieves a fuel savings of up to 16.6% and 14.7% in the IDEAL and C-V2X communication cases, respectively, for a peak hour demand on the downtown Los Angeles network considering a 50% level of a market penetration of the connected vehicles. The results demonstrate that the fuel savings increase with the increasing levels of market penetration at lower traffic demand levels (25% and 50% of the peak demand). At higher traffic demand levels (75% and 100%), the fuel savings increase with the increasing levels of market penetration with maximum benefits at a 50% market penetration rate. Although the communication system is affected by the high density of vehicles at the high traffic demand levels (75% and 100% the peak demand), the C-EEDR application manages to perform reliably, producing system-wide fuel consumption savings.The C-EEDR application achieves fuel savings of 15.2% and 11.7% for the IDEAL communication and 14% and 9% for the C-V2X communication at the 75% and 100% market penetration rates, respectively. Finally, the paper demonstrates that the C-V2X communication constraints only affect the performance of the C-EEDR application at the full demand level when the market penetration of the connected vehicles exceeds 25%. This degradation, however, is minimal (less than a 2.5% reduction in fuel savings). The C-V2X communication protocol demonstrated a reliable performance that allowed the C-EEDR application to achieve benefits even in the highest traffic demand levels (100%) and at full market penetration rates (100%) in contrast to previous studies, where the traffic system failed due to the failure of the underlying communication system used on highly congested transportation networks. The results demonstrate the importance of the C-EEDR application when applied in highly congested road networks where the application managed to achieve savings not only in fuel consumption, but also in the average system-wide travel time and the stopped delay. Conceptualization, H.A.R. and M.M.G.F. ; methodology, H.A.R. and M.M.G.F. ; validation, H.A.R. and M.M.G.F. ; writing--original draft preparation, H.A.R. and M.M.G.F. ; writing--review and editing, H.A.R. ; All authors have read and agreed to the published version of the manuscript. This work was funded by Qualcomm Technologies, Inc.  
Data Availability Statement: Not applicable.