Nowadays by increasing importance of information in all sectors, illustrating data in a communicative format helps decision makers to understand and analyze effectively large amount of information in a short time. Information visualization, as a way of presenting different data types in a more understandable form, is growing increasingly in various areas. This thesis aims to investigate how information visualization could be used to increase readability and usability of transportation simulation data. Most of the previous studies in this area have focused on visualization of transportation infrastructures such as roads, bridges, etc.; while the main focus of this thesis is visualizing the outputs of transportation simulation systems. In order to study the role of information visualization in the transportation systems, we have investigated the visualization applications in a real implemented agent-based transportation simulator called TAPAS as case. In our case study, the visualization related requirements of users were analyzed, and the visualization tool was designed and developed based on the identified requirements.