Table 1 Descriptive statistical analysis.

Genders

1

Male

133

47.2

47.2

47.2

2

Female

149

52.8

52.8

100

Age

1

18–30 years

77

27.3

27.3

27.3

2

31–40 years

76

27

27

54.3

3

41–50 years

59

20.9

20.9

75.2

4

51–60 years old

39

13.8

13.8

89

5

61–70 years old

31

11

11

100

Educate

1

Junior high school and below

21

7.4

7.4

7.4

2

High school/Secondary Vocational school

36

12.8

12.8

20.2

3

College

107

37.9

37.9

58.2

4

Undergraduate

102

36.2

36.2

94.3

5

Postgraduate and above

16

5.7

5.7

100

Careers

1

Civil servant

16

5.7

5.7

5.7

2

Public institution employee

20

7.1

7.1

12.8

3

Corporate employee

136

48.2

48.2

61

5

Self-Employed

62

22

22

83

6

Student

22

7.8

7.8

90.8

7

Others

26

9.2

9.2

100

Annual Income

1

Less than 30,000 RMB

53

18.8

18.8

18.8

2

30,000–50,000 RMB

81

28.7

28.7

47.5

3

50,000–100,000 RMB

20

7.1

7.1

54.6

4

100,000–150,000 RMB

52

18.4

18.4

73

5

150,000–200,000 RMB

41

14.5

14.5

87.6

6

200,000 RMB and above

35

12.4

12.4

100

Frequency of using underground parking garages

1

Daily

115

40.8

40.8

40.8

2

3–5 times per week

81

28.7

28.7

69.5

3

1–2 times per week

64

22.7

22.7

92.2

4

Occasionally

22

7.8

7.8

100

Driving experience

1

Less than 1 year

35

12.4

12.4

12.4

2

1–5 years

72

25.5

25.5

37.9

3

6–10 years

70

24.8

24.8

62.8

4

11–15 years

45

16

16

78.7

5

16–20 years

29

10.3

10.3

89

6

21 years and above

31

11

11

100

Type of vehicle driven

1

Small sedan

107

37.9

37.9

37.9

2

Medium to large-sized vehicle

67

23.8

23.8

61.7

3

SUV/Off-road vehicle

60

21.3

21.3

83

4

Microcar

48

17

17

100