Interactions with vehicles ahead, response to traffic controls, desired speed, and lane-use preference determine the movements of vehicles. These interactions are manifested in lane change decisions and acceleration and deceleration rate applied at any given time. The simulator maintains a linked list of vehicles in each lane and moves individual vehicles according to the car-following, lane changing, and event response models described in this section. The car-following model computes the acceleration or deceleration rate of a vehicle in terms of its relationship with the leading vehicles; the lane changing model represents the behavior of switching lanes; and the event response model captures drivers' responses to traffic signals and signs, incidents, and toll booths.