## 4 Discussion
### The PUTSS Algorithm Scenarios  
The results of the five scenarios show that the PUTSS algorithm has dynamic decision-making capabilities in real-time urban transportation management. Furthermore, the algorithm can adjust bus schedules by optimizing service for passengers while minimizing operational costs for the transport provider.  
The benefits of employing the PUTSS algorithm are as follows:  
1. Fewer empty buses on the road. One of the leading environmental issues with traditional bus systems is the inefficiency of buses running on fixed schedules, even when there is little or no demand. This results in buses traveling with few or no passengers, wasting fuel and resources. The PUTSS algorithm adapts to real-time demand, ensuring that buses run only when and where needed. This reduces the number of empty or underutilized buses on the road, directly cutting down fuel consumption.
2. Lower CO2 emissions. By optimizing the schedule, the PUTSS algorithm reduces the time buses spend idling in traffic or running off schedule. Efficient routes mean less fuel is burned per trip, which translates to lower CO2 emissions, an essential requirement in smart cities. Given that, nowadays, in most cities, buses are often diesel-powered (and their electrification is just beginning), which produces higher levels of pollution than gasoline, even small reductions in bus trips or fuel usage can have a significant impact on overall emissions.
3. Less traffic congestion: When buses run more efficiently, with fewer vehicles on the road at unnecessary times, there is a reduction in overall traffic congestion. This, in turn, means that other vehicles (cars, trucks, etc.) can move more smoothly, leading to less stop-and-go traffic. Vehicles burn more fuel when constantly stopping and starting, so reducing congestion by the PUTSS algorithm helps improve fuel efficiency and lowers emissions across the entire transportation network in a smart city.
4. Encouraging public transportation use: A more reliable and optimized bus schedule by the PUTSS algorithm improves the overall experience for passengers, making  
Figure 4: Actions taken: (**a**) the bus departs as scheduled and (**b**) the next bus is canceled.  
public transportation a more attractive option. As more people choose buses over personal cars, the number of individual vehicles on the road decreases. This shift from private vehicles to public transport can significantly reduce the total emissions of a city, as fewer cars are needed to move the same number of people.
5. Supporting sustainable urban growth. Smart cities need to optimize public transportation systems to grow sustainably. Reduced emissions and better resource use contribute to cleaner air quality and lower noise pollution, enhancing the overall environmental health of urban areas.  
A drawback of the PUTSS algorithm lies in the empirically set reserve value of five for the passenger margin reserve, which implies that the algorithm may not adjust dynamically to minor passenger fluctuations, potentially leading to underutilization or overburdening of buses. This static approach could limit responding to real-time changes in passenger demand across different times of the day or in response to unforeseen events like weather changes or special events.  
Another identified limitation is when a trip is skipped based on the algorithm's decision. Buses often wait unnecessarily at the terminal until their next scheduled departure time. This waiting time incurs operational costs and may lead to inefficiencies in resource utilization, as buses could have been deployed more on alternative routes or schedules.