Abstract: Opening gated community can extend urban road network to some extent and help to alleviate traffic congestion. However, the decision-making approach in the current gated community opening plan is single layer and has not consider the vehicle emission and traffic noise pollution brought to the community after the opening. This paper used the minimum cost function value as the optimization goal and developed a bi-level decision-making model with upper-layer as optimal system cost and lower-layer for user balance. Three decision-making methods were introduced in the model: whether the gated community is open, one-way or two-way travel, and speed limit on the road. The genetic algorithm was used to solve the upper-layer model and the Frank-Wolfe algorithm was used to solve the lowerlayer model. The validation analysis of the model shows that the relative deviation of the optimal solution cost value obtained from the model is 0.67%, and the average year-on-year cost saving is 11.8%. The comparative analysis shows that the reasonable setting of three decision-making methods for the opening of gated community can reduce the travel time and detour distance of vehicles, thereby reduce the travel cost and the additional cost considering the impact on the environment. A relatively high posted speed limit helps to reduce the total travel cost.

Key words: urban traffic, open decision-making approach, bi-level model, gated community, environmental impact of traffic

摘要： 封闭小区的开放可以增加城市道路网密度，缓解交通拥堵，但目前封闭小区开放方案的决策方式单一，且未考虑开放后给小区带来的汽车尾气和交通噪声污染问题。将交通环境影响纳入考量范围，以行程时间、尾气排放和交通噪声构成的总目标费用函数值最小作为优化目标。引入封闭小区是否开放、单双行和限速这3种决策方式，建立上层系统费用最优和下层用户均衡的封闭小区开放双层决策模型，并利用遗传算法和Frank-Wolfe算法分别对上、下层模型进行求解。 对模型优化效果进行验证分析，结果表明，所建模型最优解的费用值相对偏差为0.67%，应用此模型后同比节省费用平均值为11.80%。对比分析得到：合理设置封闭小区开放的3种决策方式，可 以减少车辆行程时间和绕行距离，降低出行者的出行费用和考虑交通环境影响的附加费用，且采取相对较高的限速值有利于降低出行总费用值。

关键词: 城市交通, 开放决策方式, 双层模型, 封闭小区, 交通环境影响