Effects of Warning Systems on Longitudinal Driving Behavior and Safety under Fog Conditions*

In this paper, we discuss the impacts of the fog warning systems on driving behavior and traffic safety under different fog conditions. Firstly, in order to obtain the driving data, an empirical driving simulator platform was established based on a real-world road in Beijing. The comparison study was conducted for eight scenarios which comprise four warning systems under fog conditions. Thirty-five test drivers drove an instrumented vehicle eight times, 2 fog conditions (light fog, heavy fog) × 4 systems (No warning, Dynamic Message Sign only, On-Board Unit only, On-Board Unit & Dynamic Message Sign). The results show that intelligent warning systems could be beneficial to driving behavior and traffic safety. Meanwhile, the vehicle-to-vehicle warning system can significantly optimize individual driving behavior. It is suggested that proper warning systems should be considered for different fog conditions since they have different effect. The study results are helpful to select proper information release form in the context of connected vehicle.