|M.Sc Student||Miran Khwais|
|Subject||Optimal Bus Priority Control with Pre-signal|
|Department||Department of Civil and Environmental Engineering||Supervisor||Professor Haddad Jack|
|Full Thesis text|
Delay imposed on buses is witnessed at isolated signalized intersections. The main source of delay is created due to bus and car interactions. Additionally, inexpensive solutions that do not involve new infrastructure are the most desired. As a result, optimization of signal control systems is needed such that it compromises between public transportation and private vehicles by minimizing total person delay in the system. Towards reducing person delay, pre-signal lights are installed at the upstream of the intersection. Pre-signal is a control tool that can manage the interaction and space conflict between cars and buses at the mixed lanes, located after the pre-signals, approaching the intersection.
This research presents an optimal pre-signal control system that optimizes signal settings based on minimization of person delay. The developed model compromises of a simplified signalized intersection with one approach, where two pre-signal lights are located, one for bus lane, and one for car lane. A continuous-time model is first developed to describe the queue lengths dynamics for the mixed lanes after the pre-signals and the bus and car lanes before the pre-signals. The optimal solutions are derived analytically via Pontryagin Maximum Principle, and the optimal pre-signal control policy is determined and synthesized.
The analytical solution found was verified through the use of the optimal control software, DIDO, which uses an advanced optimization method and solves complex dynamic optimization problems without prior knowledge of the analytical computations or the solution. Four examples are used to test and analyze the derived solution. Different variables of interest were selected to plot, for the sake of comparison. The numerical results for each example are demonstrated through presenting the evolution of each variable of interest in time. This is important because it offers a better understanding of the system used, where the exact effect of each variable is analyzed.