## 8 Conclusions and Discussion for Future Investigations
It is to be mentioned that the findings obtained might also be extended to other one-way road tunnels with similar characteristics, in which hydrants are not yet provided and sidewalks and emergency exits are temporarily unavailable as escape routes in the event of a fire. Although the findings show the effectiveness as a temporary safety measure of the emergency vehicle stationed at the tunnel portals and equipped with a micronized water system, a possible extension of this study might also be to investigate the influence of droplets (i.e., size, air speed, and orientation) to make further progress in research. In addition, it is necessary to underline the necessity that Tunnel Management Agencies accelerate the refurbishment works for making road tunnels definitively safer for users in a short space of time. Generally speaking, it is to be said that the prevalent topics in the field of tunnel safety engineering are fire investigation and traffic crashes analysis; certain applications of the latter question can be found in more detail in [PERSON] and [PERSON] [36], and [PERSON] et al. [37; 38; 39; 40]. Without a doubt, many studies have been carried out on the two mentioned subjects; however, given the essential role of tunnels in the functionality of a transportation network, the resilience of these structures should be investigated in greater depth. In this respect, traffic simulation tools should be more applied especially. Some practical uses of the simulation tool can be found in [PERSON] and [PERSON] [41], [PERSON] and [PERSON] [42], [PERSON] [43], and [PERSON] et al. [44]; however, these studies do not address the issue of tunnel resilience. Low flammability of road pavements within tunnels might be another important question of research for limiting the release of toxic gases due to burning asphalt materials in the event of a fire. Pavements that employ materials inert to the combustion process, or in cement concrete (the behaviour of which under traffic can be seen, for example, in [PERSON] and [PERSON] [45]), might be suitable for this scope. Finally, it appears useful also to mention that it is worth investigating the risk level due to the transit of the Electric Vehicles (EVs) through tunnels for the significant releases of toxic gases in the event of battery fire. The aforementioned lack of knowledge needs to be filled by future studies in order to make further progress in the field of tunnel safety. Conceptualization, C.C., G.G. and I.R. ; methodology, C.C., G.G. and I.R. ; software, C.C., G.G. and I.R. ; validation, C.C., G.G. and I.R. ; formal analysis, C.C., G.G. and I.R. ; investigation, C.C., G.G. and I.R. ; data curation, C.C., G.G. and I.R. ; writing--original draft preparation, C.C., G.G. and I.R. ; writing--review and editing, C.C., G.G. and I.R. ; visualization, C.C., G.G. and I.R. ; supervision, C.C. All authors have read and agreed to the published version of the manuscript. This research received no external funding. Not applicable. Informed Consent Statement: Informed consent was obtained from all subjects involved in the study. Data Availability Statement: The data presented in this study are available on request from the corresponding author. The data are not publicly available due to privacy restrictions. The authors declare no conflict of interest.