Research on effect of combinative speed control devices based on driver load questionnaire

Different kind of speed control devices may carry different message load to a driver. Most research are focus on decide the speed difference with before and after test, and few pay attention to the effect of driver load. From the view of driver load, the purpose of the paper is to analyze in detail effect of various speed control devices and combinative speed control devices by driver load questionnaire, and to find the best effect of combinative speed control devices, which can promote service level and ensure driving safety.