## 2 Concept Definition and Calculation  
### Factors Influencing the Health of Public Transportation Operations  
The public transportation operation system is a complex and comprehensive system formed by the interaction of passengers, vehicles, road network, and environment. Different factors influence each other, and they are subject to mutual constraints. At the same time, it is also subject to the interference of other contingent uncertainties. The stability and efficiency of public transportation operation is also characterized by randomness. The diagram of the public transport operation process is shown in Figure 1.  
Figure 1: Diagram of bus operation process.  
The scope of this paper is limited to the single-route bus operation level, analyzing the whole process of vehicles starting from the first station, traveling on the roadway, stopping at stations and intersections, and finally arriving at the last station; thus, it does not involve the bus network structure and station arrangement, bus route repetition number, non-linear coefficient, and other influencing factors at the bus planning level. Only the road delays, cross delays, and station delays in bus operation are diagnosed and analyzed, and improvement suggestions are made for different types of key influencing factors.  
(1) Road delays  
In the process of bus operation, the travel time of the vehicle running on the road section accounts for a large part of the full running time of the bus vehicle. Roadway congestion can lead to an increase in travel time for bus operations. During bus operations, especially during peak periods, the traffic volume on the roadway increases significantly, and traffic will run slower, affecting the speed of bus operations; therefore, road delays are a major influence on the health of bus operations.  
(2) Intersection waiting time  
Bus vehicles in the process of operation, the intersection encounter red light queue, and the time generated by the delay are also an important factor affecting the health status of public transport operations, and through the intersection of the time generated by the proportion of delay compared to the delay generated by roadway congestion, the difference is not large. The longer the bus waits in line at the intersection, the longer the delay will be and the worse the health of the bus operation will be. If the delay of bus vehicles is not reduced through signalized intersections, bus operational health cannot be improved effectively.  
(3) Stopping time  
Bus stopping process refers to the bus vehicle from slowly decelerating into the bus station, and then slowly accelerating away from the bus station into the process of traffic. The characteristics of public transport itself refer to the following: it is decided that the bus at each stop to have a slowdown and stop and speed up the process of leaving. The number of passengers boarding and alighting from the station, whether or not the ticket is automatic, etc., will affect the stopping time, which in turn affects the overall health of the bus operation. The more there are stops, the higher the passenger volume will be, and the longer the stop time will be.  
(4) Other factors  
Driver driving behavior, weather conditions, and other factors will also affect the bus running conditions. Different drivers have different personalities and are familiar with different degrees of bus vehicles, which can also affect the vehicle running delays; different weather conditions and different bus vehicle performance may also affect the bus operation. As the 101 bus for a fixed departure interval, thus the impact of the departure interval on the bus operation is not considered in this paper.