Models And Optimizations Of Bus Route System Based On The Theory Of Cellular Automaton

The rapid economic development leads to the improvement of the urbanization level and motor vehicle population, and traffic congestion has become the main bottleneck restricting cities’ sustainable development. Based on the previous management methods and theories, public transportation plays an effective role in relieving the traffic congestion. However, public transit systems also face various problems, such as bus bunching, inaccurate schedule, unbalanced bus loads, et al.. To solve these deficiencies, it’s important to survey the characteristics of bus running and optimize bus route system.The bus route system is modeled with the cellular automaton, and the characteristics and optimizations of single bus route and collinear bus routes are researched in this paper. The paper mainly works as follows:(1) Based on the NaSch model, a cellular automaton model of bus route system under open boundary condition is established with consideration of the OD distribution of passenger trips. The supply-demand relationship of bus route system can be calculated by the three indexes of maximum bus loads, bus departure time and average passenger’s arrival time, and the supply-demand balance line can be gained.(2) Considering the categories of massive spatial-temporal graphs of the single route, different phase states of the system are found, including congestion state, bunching state, and homogeneous state. For each phase state, there further exists insufficient capability situation and sufficient capability situation. It is found the satisfied operation parameters locate near the supply-demand balance line. Comparing simulation results with Beijing Bus single bus route system investigation, some similarities are found.(3) Through massive numerical simulations of collinear routes system, it could decrease the waiting time of passengers obviously by increasing bus departure frequency and relatively more interchange stations. The dwelling time of buses in interchange station could be decreased obviously by increasing the number of interchange station. Comparing simulation results with Beijing Bus collinear bus routes system investigation, some similarities are found.