## 2 Concept Definition and Calculation
### Definition of Eigenvalues of Influencing Factors  
To quantify the impact of different influencing factors on the health of bus operations, it is necessary to first calculate the characteristic values of the influencing factors. This study defines and quantifies the main factors affecting bus operation including roadway delays, intersection delays, and stop time delays based on existing road network conditions from existing data.  
(1) Station delay  
Station delay is directly expressed by the stopping time, which refers to the time from when the bus vehicle slows down to enter the platform to when the bus leaves the platform completely, as shown in Figure 2.  
\[T_{s}=T_{sl}-T_{sa} \tag{1}\]In Formula (1), \(T_{s}\) represents the stopping time. \(T_{sl}\) refers to the moment when the bus leaves the station. \(T_{sa}\) refers to the moment when the bus arrives at the station. In the case of bus vehicle positioning data, within 50 m from the station and the speed is less than 8 m/s marked as a stop, if the minimum speed within 50 m of the station is greater than 8 m/s, marked stopping time is 0.  
(2) Cross delay  
Due to data limitations, only bus vehicle operation data were obtained, and this study was not able to calculate delays in combination with intersection traffic, which was calculated directly from bus operation GPS data. Cross delay refers to the delay time from the time the bus enters the intersection and slows down until the bus leaves the intersection completely [31], as shown in Figure 3, Cross delay diagram.  
\[T_{c}=(T_{cl}-T_{ca})-\frac{2R}{v_{f}} \tag{2}\]  
In Formula (2), \(T_{c}\) represents the cross delay. \(T_{cl}\) refers to the time the bus leaves the intersection. \(R\) refers to the intersection impact range, urban road intersection sight distance taken 30 m, plus the intersection center to the parking line between the distance of about 20 m. Therefore, take the intersection center point before and after 50 m as the intersection impact range. \(v_{f}\) is the free flow speed, equal to the highest roadway speed. The cross delay is equal to the difference between the travel time for 50 m before and after each intersection and the time taken to travel the same distance at free flow speed.  
(3) Road Delay  
Road delay refers to the delay time from the bus traveling on the segment between intersections, as shown in Figure 4.  
\[T_{l}=(T_{ca(i)}-T_{cl(i-1)})-\frac{l}{v_{f}}-T_{s} \tag{3}\]  
Figure 4: Road delay diagram.  
Figure 3: Cross delay diagram.  
Figure 2: Station delay diagram.  
In Formula (3), \(T_{l}\) refers to the road delay. \(T_{ca(i)}\) refers to the time in leaving the area of influence of the intersection. \(T_{cl(i-1)}\) refers to the time the bus leaves the \((i-1)\) intersection. \(l\) refers to the actual distance the bus runs between two intersections. \(T_{s}\) refers to the station delay. For bus operations, a bus stop may be passed between two intersections. Hence, the station delay needs to be subtracted from the real road delay.  
(4) Weather factors  
In this paper, we studied the data of bus operation from 21 November to 25 November 2016 with weather conditions as shown in Table 1 below. The weather conditions varied during the five days. Separate values are assigned for different weather.  
(5) Driver driving behavior factors  
Route 101 was assigned 18 vehicles from 21 November to 25 November according to the mapping relationship between license plates and routes. The license plates were assigned values 1-18, respectively, as a way to study the impact of different drivers' driving behaviors on the health of bus operation.  
Driver driving behavior and other vehicle factors will also affect the bus running conditions. Different weather conditions may also affect the bus operation. As the 101 bus for a fixed departure interval, the impact of the departure interval on the bus operation is not considered.