Abstract: Urban traffic control models are one of the basic tools for the analysis and design of transportation systems. The author develops a urban traffic control model and derives the optimality conditions of traffic control by optimization theory and Lagrangian function. Traffic control model is formulated as an equilivalent variational inequality where the variables are green time of phases of in teractions.

Key words: urban traffic control, variational inequality formulation, signal setting

摘要： 城市交通控制模型是交通网络系统分析和设计的基础工具之一。本文基于交通网络系统费用最小原则研究了城市交通控制的优化模型；根据最优化原理 Lagrangian算子性质，得到交通控制信号配时的最优性条件，提出并证明一个与之等价的新的城市交通控制模型--基于绿灯时间的变分不等式模型，提出算法并给出算例。

关键词: 城市交通控制, 变分不等式, 信号配时