Application of qualitative approach in transportation and traffic studies

Quantitative approach is known as a kind of research methods, has been used when measurable parameters are available in the process of research. This kind of research methods is being used in transportation and traffic fields because of the availability of measurable parameters. Although there is some measurable parameters are available, in the recent years qualitative and combined (quantitative and qualitative approaches)approaches have been used in transportation and traffic studies. In this paper a review study has been done to eliminate using qualitative approach in transportation and traffic studies. Results showed that although a number of variables are defined by measurable parameters in the field of traffic and transportation, but qualitative methodologies inresearch process, have been used in many cases. Results also show that in some studies qualitative approach had results that are more appropriate because some of the social parameters particularly in urban transportation have been merged by measurable parameters.