Signal Control Strategies for Bottleneck Area on Urban Expressway

Urban expressways in China have special features. Distance between on-ramp and off-ramp is relatively shorter compared with that in developed countries (normally longer than 1000 m), and off-ramps are usually connected with urban streets and intersections. Thus successful ramp control strategies used in Europe or U.S. may not be suitable in China. This paper first analyzes traffic flow characteristics at representative “bottlenecks” in Beijing urban expressways. Efforts are devoted to improve the capability of traffic simulation platform to simulate detailed traffic behaviours by calibrating simulation model parameters. Efficiencies of different signal control strategies in road network involving on-ramp, off-ramp, adjacent streets and intersections are compared. Results indicate that combing adaptive ramp control with synchronization signal control strategies is an effective way to enhance road capacity and alleviate congestions in urban expressways.

摘要中国的城市快速路有着与发达国家相比截然不同的特征。中国城市快速路匝道出入口之间距离相对较短，且城市快速路匝道出口经常与城市道路交叉口相连，因此在欧美成功应用的快速路匝道控制方案不一定适用于中国。本文详细描述了如何在仿真中设置模型参数使得城市快速路交通流特性仿真结果与实际测量值具有较高的匹配精度。在具体阐述自适应与协同信号控制策略的基础之上，给出了各种方案在匝道入口、出口辅路和出口下游交叉口的具体部署方案。最终仿真结果表明，自适应和协同控制策略能够提高瓶颈区域道路通行能力8%–9%，有效地缓解城市快速路交通拥堵。