0 = Female
1 = Male

Main Occupation
1 = Student
2 = Employee
3 = Self-employed
4 = Unemployed
5 = Retired
6 = Household
7 = Other

Educational level
0 = None
1 = Primary Studies
2 = High School
3 = Technical Training
4 = University (Undergraduate) Degree
5 = University (Post-graduate) Degree

Text messages or chats
0 = No
1 = Yes

1. Been able to concentrate on whatever you are doing
1 = Never
2 = Sometimes
3 = Frequently
4 = Always

Traffic Crashes (5 Years)
0 = No
1 = 1
2 = 2
3 = 3
4 = 4
5 = 5

Age Group (5 intervals)
1 = <26
2 = 26-35
3 = 36-45
4 = 46-55
5 = >55