Traffic oscillations often occur in road traffic, they make traffic flow unstable, unsafe and inefficient. Emerging connected and\nautonomous vehicle (CAV) technologies are potential solutions to mitigating the traffic oscillations for the advantages that CAVs\nare controllable and cooperative. In order to study a control strategy and the effectiveness of CAVs in mitigating traffic oscillations\nand improving traffic flow and analyse the characteristics of homogeneous traffic flow made up of CAVs and heterogeneous traffic\nflow made up of CAVs and RVs when traffic oscillations appear in traffic flow. Firstly, the formation and propagation of traffic\noscillations in a platoon of RVs are simulated and analysed. Then, a car-following control model is built to control the longitudinal\nmotion of CAVs, and real-time information of preceding CAV is used in the model and this can make the motion of CAVs more\ncooperative. The model reflects an idea named â??slow-inâ? and â??fast-out,â? and this idea is helpful to mitigate traffic oscillations. Then,\nnumerical simulations of homogeneous traffic flow of a platoon of CAVs and simulations of heterogeneous traffic flow containing\nCAVs and RVs are conducted, and different penetration rates (0, 0.2, 0.4, 0.6, 0.8, and 1) of CAVs are considered in the simulations of\nheterogeneous traffic flow. The characteristics and evolution of traffic flow are analysed and some indexes reflecting traffic efficiency\nand stability are calculated and analysed. Simulation results show that there are smaller velocity fluctuation, less stopping time and\nshorter length of road occupied when vehicle platoon contains CAVs (penetration rates are from 0.2 to 1) compared to the platoon\ncontaining only RVs (without CAVs). As for the heterogeneous traffic flow containing CAVs and RVs, these three indexes decrease\nwith the increase of penetration rates (from 0.2 to 1) of CAVs. These results indicate that CAVs with the car-following control model\nin vehicle platoon are beneficial for mitigating traffic oscillations and improving traffic flow.
Loading....