Cellular automata models for signalised and unsignalised intersections with special attention to mixed traffic flow: a review

Present study reviews simulation models available for signalised and unsignalised intersections using cellular automata (CA). CA models are discrete dynamic systems, through which it is possible to model traffic behaviour with ease and simplicity. Thus, CA was chosen for the study. Driver, seepage behaviour and type of traffic (homogeneous/heterogeneous) affect the capacity and safety of the intersections. These models can be either with open boundary (with continuous deletion and generation of vehicles) or closed/periodic boundary (with a fixed number of vehicles). The proposed study also investigates about the boundary conditions of simulation models as these change the results of simulations. Further, frequent acceleration/deceleration activity at the intersection causes more emissions. It was found that most of the traffic simulation models developed for intersections lack in modelling interaction between vehicles, seepage, driver behaviour and emission behaviour etc. Very few studies were found to model the emission behaviour with CA. Present study chronologically lists studies with methods adopted, advancements in those methods, traffic behaviours taken into consideration and missing gaps between studies. The composition and interaction of five different modes such as cars, buses, trucks, motorised three-wheelers and motorised two-wheelers were considered as mixed traffic. A new methodology is suggested based on this review.