Effect of Slopes in Highway on Traffic Flow

In this paper, we propose a novel slope cellular automaton (CA) model to depict some physical properties of traffic flow with slopes. In our model, we present the effect of slopes on the acceleration/deceleration capabilities and safety distance of the vehicles in highways as in real traffic situations. By numerical simulations, we investigate the dependence of the vehicle capacities in highways on the length and grade of slopes. It is shown that the larger the slope grade, the more significant the effect of slopes on the traffic flow is. Especially when the slope grade is beyond a certain value (i.e. |σ| > 3%), the effect of slopes on traffic flow becomes quite markedly.