(3) Station Capacity

The capacity of the station depends on the stopping capacity of the station, its size, and the bus stop time, etc. In an actual urban public transport network, stations often serve multiple lines, and the total number of passengers carried by these lines should not exceed the capacity of the station, as constrained by Equation (12). Here, *Sc* is the capacity of the station; *Qi* is the passenger volume of line *i* in the station; *γ* is the coefficient considering the number of multiple lines and the actual impact of traffic around the site. *γ* is decided considering actual cases.

$$\sum\_{i} Q\_{i} \le S\_{i} \gamma \tag{12}$$

### (4) Road Section Unevenness Coefficient

Road section unevenness coefficient *Ki* refers to the ratio of the flow of a certain section and the average flow of the line, as denoted by Equation (13), where *Qi* is the flow of a certain section and *Q* is the average flow of the line.

$$K\_i = \frac{Q\_i}{Q} \tag{13}$$

The total network is constrained by Equations (14)–(18):

### (1) The Density of the Transportation Network

The density of the transportation network (*ρmin*) refers to the bus line length. It directly reflects the degree of proximity to the line when the residents travel by bus. For the urban central area, Equation (14) is met, while for the downtown area, Equation (15) is met.

$$3 \le \rho\_{\min} \le 4 \tag{14}$$

$$2 \le \rho\_{\min} \le 2.5\tag{15}$$

### (2) The Average Transfer Coefficient

The average transfer coefficient *T* is the ratio between the sum of the bus trips number and transfer passengers number and bus trips number, which is computed by Equation (16). Here, *T* is the average transfer coefficient, *Q*0*ij* is the number of direct trips from site *i* to *j*; *Q*1*ij* is the number of trips with one transfer from site *i* to *j*; *Q*2*ij* is the number of trips with two or more than two transfer from site *i* to *j*; *Qij* is the number of total trips from site *i* to *j*. Normally, for large cities, Equation (17) is met and for medium and small cities, Equation (18) is met.

$$\overline{T} = \frac{\sum\_{ij} \left( Q\_{ij}^0 + 2Q\_{ij}^1 + 3Q\_{ij}^2 \right)}{\sum\_{ij} Q\_{ij}} \tag{16}$$

$$T \le 1.5\tag{17}$$

$$T \le 1.3\tag{18}$$
