Abstract: The freeway systems’ efficiency will be decreased for the congestion.To eliminate the congestion，a density controller is put forward under the assumption that all vehicles’ drives instantly follow the information issued by the controller.On the macroscopic level，a density controller calculates the desired speed commands to be followed by vehicles in each section of the freeway lanes in order to achieve desired traffic density distributions that lead to optimum traffic flow conditions.On the microscopic level，each vehicle is driven according to the appropriate commands sent by the density controller.Then a real-time and effectiveness-high algorithm is designed.The simulation results guarantee exponential convergence of the traffic density at each section to the desired density and demonstrate significant benefits in terms of smooth and stable traffic flow that reduce congestion considerably.

Key words: freeway systems, controller construction, complete information followed, exponentially convergent, algorithm design

摘要： 快速路系统由于拥挤的产生而影响其利用效率。为了消除拥挤，在假设快速路系统中的驾驶员完全服从命令并能即刻调整其运行状态的基础上，提出了密度控制器的构造方法。宏观层次，此密度控制器依据最优交通状况来计算速度值，然后把所得的速度值发给行驶的车辆。微观层次，每个车辆都即刻按此速度行驶。然后在此基础上，设计了一个适时、高效的算法。仿真实例既表明了每一段的交通密度都指数收敛于期望的交通密度，同时也论证了所提方法在降低拥挤方面有显著的提高。

关键词: 快速路系统, 控制器构造, 完全信息服从, 指数收敛, 算法设计