Abstract: The traffic flow control under various bad weather conditions is the current important problem to resolve urgently. To this problem, we use the Markos Papageorgiou’s expressway traffic flow model to analyze the various weather conditions, use the nerve network method, and build up a set of suitable traffic flow model for various weathers and a control system of the entrance ramp. Next, we use the BP nerve networks calculate methods to carry on emulation, and to distinguish parameter. Conclusion is get in the end: The mathematic model and the traffic flow model witch have been built by use of the nerve network methods tally with what the actual traffic condition of the expressway under the various bad weather condition, and establish the theory and practice foundation of the traffic flow control of the expressway under the various bad weather condition.

Key words: expressway, various bad weather conditions, on-ramp control, neural network

摘要： 各种恶劣气象条件下的高速公路的交通流控制是目前急需要解决的重要问题。就此问题，我们利用Markos Papageorgiou的高速公路交通流模型对各种气象条件进行分析，使用神经网络方法，建立了一套适合各种气象条件的交通流模型和匝道入口控制系统，有效地控制恶劣气象条件下的高速公路交通事故。其次，我们利用BP神经网络的算法进行了仿真，对其中的参数进行辩识。仿真的结果与实际情况能很好地吻合，为在恶劣气象条件下控制高速公路的交通流奠定了理论和实践基础。

关键词: 高速公路, 恶劣气象条件, 匝道控制, 神经网络