Abstract
The regulation issue on excessive window tinted vehicles has been continuing. It has been believed that those vehicles causes more accidents, simply because of impeding the following vehicle driver sight. In this study, it was even assumed that those vehicles could incur the road capacity reduction by the same reason. This assumption has never been investigated in the field due to the difficulty of the precise data collection. An experimental methodology to collect the required data using RTK GPS receivers has been developed and utilized in the field data collection. According to the headways and acceleration noise analysis, it was confirmed that the window tinting affects the following vehicles in proportion of the tinting degree. A full scale analysis considering various road and vehicle conditions needs to be performed in near future.