###### Abstract
Overall, since the risk after the fire of BEVs and their ICEV counterparts was found to be equivalent, the authors concluded that tunnel ventilation systems designed in accordance with current guidelines do not need to be adapted to cope with the increasingly widespread use of BEVs. However, they pointed out that it had not yet been verified whether these conclusions are still valid in the event of a fire involving larger BEVs such as buses. [PERSON] et al. [20] conducted FDS simulations on fires involving new energy electric vehicles to analyze the effects of different blocking ratios and water mist spray angles on smoke propagation in road tunnels. The results showed that the smoke back-layering length in the upstream direction increased with the blocking ratio and that setting an appropriate spray angle significantly reduced CO concentrations while also improving tunnel visibility, which might improve the safety of escaping people. [PERSON] et al. [21] developed a numerical model, which was run using the FDS code, to assess the safety of LIBs for electric cars in the event of a fire in a naturally ventilated road tunnel. Simulations were carried out with different HRRs up to 15 MW, and the results in terms of temperature, CO, and CO\({}_{2}\) concentrations were compared with those from fuel vehicle fires. They found that BEVs produce higher temperatures, greater smoke volumes, and higher CO emissions than ICEVs, which might hinder people's evacuation and firefighter operations. [PERSON] et al. [22], by extrapolating existing data from full-scale fire tests performed on relatively small BEVs and ICEVs (e.g., cars), predicted the HRR curve over time of larger BEVs and ICEVs (e.g., large SUVs). They found that the total energy released by BEVs was consistently greater than that of the corresponding ICEVs, especially for larger vehicles. No significant difference in the HRR\({}_{\text{max}}\) was measured between BEVs and ICEVs of similar size. [PERSON] et al. [23] performed full-scale fire tests in an open-space environment to evaluate the suppression ability of compressed air foam, water spray, and fire blankets on BEC fires in the initial phases. They found that the flame was rapidly reduced when compressed air foam was used, but the battery kept releasing white gas smoke, thus requiring the application of water for a long period of time. Water spray contributed to reducing the HRR and temperature, but its low flow rate could neither extinguish fires in the passenger compartment nor stop the battery thermal runaway. Finally, fire blankets effectively extinguished the fire and controlled its propagation, but they had little effect on arresting the thermal runaway of the LIB. [PERSON] et al. [24], using the FDS code, analyzed the temperatures and CO concentrations inside an electric bus generated by the burning of only its LIB (i.e., the other components of the bus, such as the seats and curtains, are not assumed to be combustible), considering different wind speeds, ventilation areas, and window opening positions. They found that in the event of a BEB fire, the risk for its occupants can be minimized by opening 100% of the windows and opening the rear window first. The results emerging from the above chronological literature review are evidently conflicting. It is still not completely clear whether BEV fires in confined spaces such as road tunnels can pose a more serious threat to the safety of the users and rescue teams when compared to the fire of similar ICEVs, thus indicating a gap in knowledge. Moreover, it is worth pointing out that most of the above-mentioned studies have compared the fire consequences of BEVs and ICEVs of relatively small sizes (i.e., cars and vans), while very few authors have investigated larger vehicles such as buses. Since battery electric buses (BEBs) are generally powered by larger-capacity traction batteries, their fire is expected to pose a greater hazard to human health than that due to the burning of BEVs such as cars and vans.