## 4 Results from the Literature Review
### On-Demand Public Transport  
On-demand public transport is a flexible transit system that adjusts to individual passenger needs in real time. Unlike traditional transport options, such as buses or trans, which operate on fixed schedules, on-demand services respond dynamically to user requests submitted through mobile apps or booking systems [46]. Research underscores the economic benefits of this approach for transport operators. With the flexibility to adjust to fluctuating demand, service providers can achieve cost savings by optimizing routes and schedules while reducing empty vehicle trips. However, on-demand public transport is noted to be especially beneficial in smaller urban areas, where demand can be more unpredictable [285; 286]. Studies on bus transit have shown that on-demand systems \begin{table}
\begin{tabular}{c c} \hline \hline
**Solution** & **Role in Case of Potential Crises** \\ \hline \multirow{7}{*}{In-vehicle air quality monitoring systems} & * Lowering the costs of running transportation operations—less fuel or energy consumption (economic crisis) * Reduction of fuel or electricity consumption (environmental crisis and health crisis) * Increasing passenger safety through the ability to monitor air quality and reduce the spread of viruses (health crisis) \\ \hline \multirow{7}{*}{Contactless payment systems} & * Lower costs related to the production, distribution, and storage of tickets, and no need to engage employees to conduct sales (economic crisis) * Increased demand for public transport travel due to speed and convenience of payment—decrease in use of private vehicles (economic crisis and environmental crisis) * Higher sanitary safety of travelers by eliminating contact with staff, touching cash, and using ticket machines (health crisis) \\ \hline \multirow{7}{*}{Smart stops and stations} & * Increase overall transportation efficiency and improve comfort for users (economic crisis) * Support in terms of accessibility for different user groups (economic crisis and social crisis) * Reducing greenhouse gas emissions and improving air quality through integration with other innovative solutions (environmental crisis and health crisis) \\ \hline \hline \end{tabular}
\end{table} 
Table 14: _Cont._reduced average travel times by 30% over a weekly cycle. Additionally, vehicle occupancy rates increased from 8% to over 50%, and emissions per passenger dropped by over 70% compared to traditional scheduled buses [47]. These findings highlight the alignment of on-demand transport with sustainable transport objectives. Other studies highlight the effectiveness of the on-demand system in response to epidemic threats, as evidenced during the COVID-19 pandemic [287]. The primary benefit was the enhanced resilience of the public transport system to disruptions, enabled by the system's flexible adaptation to varying threat levels and mobility restrictions [146; 288]. In-vehicle air quality monitoring systems are sophisticated technologies that enable real-time monitoring and assessment of air quality within the vehicle cabin. Equipped with sensors to measure carbon dioxide, oxygen levels, and other compounds, as well as monitoring humidity and temperature, these systems provide vital information to drivers and passengers, helping reduce health and safety risks associated with extended time in enclosed spaces [289; 290]. Air quality monitoring systems can enhance vehicle energy efficiency by adjusting HVAC functions based on current cabin air quality. This helps to lower fuel consumption and, most importantly, energy usage in electric and hybrid vehicles, reducing overall operational costs for transport providers [291]. Research also highlights the importance of this solution for advancing sustainable transport. By managing cabin air quality--particularly in electric vehicles--emissions are reduced both inside and outside the vehicle. This minimizes the need for frequent external air circulation, which in turn helps reduce energy consumption [292].