Table 1 Minimal adequate models for Anhui, Henan and Chongqing

Intercept

− 182.68

[− 367.70,11.33]

−1.54

254.03*

[61.49,446.58]

2.16

348.50***

[327.49,369.51]

27.20

School summer vacation

−89.79***

[− 124.99,-54.59]

−4.18

−15.22

[− 88.17,57.73]

−0.34

− 107.91**

[− 155.54,-60.28]

−3.72

School winter vacation

9.63

[−25.86,45.14]

0.45

183.90***

[118.9248.88]

4.64

− 104.61**

[− 158.37,-50.85]

−3.19

Spring Festival

(4 wks delay)

100.7***

[59.22,142.18]

3.98

394.87***

[331.8457.93]

10.27

191.72***

[143.88,239.56]

6.57

Highway passenger traffic (4 wks delay)

9.48***

[5.91,13.05]

4.35

10.58***

[6.16,15.01]

3.91

–

–

Relative Humidity (%)

6.30***

[4.17,8.43]

4.85

6.38**

[3.43,9.33]

3.55

–

–

Temperature (°C)

–

–

–

–

–

–

Sunshine (hours)

1.95**

[1.03,2.86]

3.50

–

–

–

–

Rainfall (mm)

–

–

–

–

–

–

Adjusted Multiple R²

0.88

0.89

0.72

F-statistic

30.66

43.69

22.86

Degree of freedom

19

20

22

p-value

8.54e-9

4.34e-10

5.91e-7