UC Irvine

While traffic light is used to coordinate vehicular and pedestrian traffics in order to provide safety to drivers on streets, there are delays and accidents resulted from unorganized signal timing and poor network design. At every signalized intersection at the yellow light onset, drivers have to make an uncertain decision in an area called the dilemma zone. It is where the drivers have to decide whether he can stop safely by the stop line or clearly proceed through the intersection. Because of the potential safety issues from the dilemma zone, this thesis attempts to simulate traffic flow in a single-lane ring road with and without the presence of a traffic signal by using the Optimal Velocity (OV) car-following model. In particular, a beacon vehicle is selected as the first vehicle to stop, and all following vehicles have to stop accordingly. Using programs such as MATLAB and CodeSkulptor, the simulation demonstrates the leading and following vehicles’ behavior with location and speed trajectory diagrams and it is found that the OV model produces a collision-free scenario even under the presence of a traffic signal. In addition, by observing a single vehicle’s behavior, some asymptotic traffic patterns can be seen. This thesis can serve as a fundamental study to inspire and develop potential dilemma zone protection to promote intersection safety and prevent risks such as rear-end accidents and red light violations.