Numerical study of urban traffic flow with dedicated bus lane and intermittent bus lane

Based on the cellular automaton traffic flow model and the concept of public transport priority, a two-lane traffic model with an intermittent bus lane is proposed and the properties of urban traffic flow are studied. The cases of traffic with a dedicated bus lane (DBL), an intermittent bus lane (IBL) and an ordinary two-lane traffic are simulated, and comparisons in the form of the fundamental diagrams and the velocity-density profiles are made between them. It is shown that the DBL has the advantage of freeing buses from traffic interference and also has the disadvantage of disrupting traffic, the IBL is more efficient in improving the bus flow than ordinary two-lane traffic and maintaining the car flow at a higher level at the same time than the DBL, while the ordinary two-lane traffic suppresses public transportation and is not advantageous in easing urban traffic congestion. Also it is indicated that the DBL is only appropriate for low traffic flow in a two-lane traffic system, and this limitation can be partly overcome by opening the bus lane to general traffic intermittently when the bus lane is not in use by buses.