Modelling a vehicle’s speed fluctuation with a cellular automata model

As is well known, a vehicle’s speed fluctuation has significant impact on traffic capacity, road safety, fuel consumption, and exhaust gas emission. Considerable microscopic traffic models have been developed in past decades, while the ability of describing the realistic speed fluctuation has rarely been examined. With the data from real traffic, in this study we investigate the performance of two typical car-following models on modelling speed fluctuation. Our findings indicate that neither of them can mimic a realistic speed fluctuation with high accuracy. In addition, it is found that the model with the minimum speed error does not necessarily mean it can describe speed fluctuation most realistically. To simulate this phenomenon more accurately, by introducing a reasonable duration of stable speed, we propose one kind of cellular automata model. Simulation results show that the model depicts a vehicle’s speed fluctuation with higher fidelity, relative to two typical models.