How does a driver perceive risk when making decision of lane-changing?

This paper shows a case study to show how a driver perceives driving risk in order to model decision making of changing lanes. Lane-changing data are collected under 28 driving conditions through a driving simulator. Analyses are focused on driver's risk perception to a leading vehicle driving on the host lane and nearest rear and front vehicles driving on a targeted lane. The analyses are operation on two stages when a driver decides to change lanes (i.e., turning on turn signal), and then when he or she is cutting in the target lane in order to comprehend lane-changing decision making. The results suggest that a driver tends to prefer the time to collision (TTC) to the time headway (THW) to the rear vehicle. When the host vehicle is cutting into the target lane, a driver tends to perceive the traffic condition through both TTC and THW. Meanwhile, it is also implied that a driver tries to grasp status of each of related vehicles driving around the host vehicle for executing lane-changing behavior. These findings illustrates driver's risk perception of making a decision and operating lane-changing behavior, which suggests it is valid to model lane-changing decision making via perceiving driving risk.