Abstract
Recently, the technology of safety driving and cruise assistance services has been being introduced in many ITS devices. By the increased number of vehicles with ITS devices, there would be traffic conditions where both vehicles with and without ITS devices are running in the road environment. In this study, influences toward driver behavior of following vehicles when preceding vehicles had either ITS devices or not was examined using a driving simulator. Comparative evaluation was also conducted between in-vehicle ITS device and variable message sign on roadside when safe driving and cruise assistance services were given to driver.