Abstract:

To improve the capacity of the continuous flow intersections and eliminate the conflict between leftturn bicycles and through vehicles at the main signal, an optimization design method for left- turn bicycles is proposed. A linear programming model is established to achieve the maximum capacity of vehicles with the consideration of many constraints, such as phase plan, cycle length, green time, and so on. The optimization effects for this design are validated by a case study and sensitivity analyses. The results show that intersection capacity can be prominently improved using the design method for left-turn bicycles, under the condition of relatively large saturation, which makes the over-saturated intersections to be under-saturated. Moreover, it is helpful to reduce the intersection delay at the low or high flow levels. Further discovered, on average, 4.5% increase in the improvement of capacity can be obtained by 100 left-turn bicycles per hour increase or 1.5% through vehicle percentage increase (when the percentage of through vehicles is more than 40%).

Key words: traffic engineering, traffic design, linear programming, continuous flow intersections, left turn bicycles

摘要：

为了提升连续流交叉口的通行能力，消除其主信号处左转非机动车与直行机动车的冲突，提出了一种左转非机动车优化设计方法.优化模型以机动车通过量最大为优化目标，考虑了信号相位相序、周期时长、绿灯时长等约束条件，建立线性规划优化模型.通过案例和敏感性分析，验证了该设计方法的优化效益.研究结果表明，该方法不仅能在高流量情况下显著提升交叉口通行能力，使得原本处于过饱和状态的交叉口变为不饱和，而且在高流量或低流量情况下，都有助于减少交叉口延误.进一步发现，左转非机动车流量每增加100辆/h或直行机动车流量比例每增加1.5%(直行机动车流量比例大于40%)，优化设计对机动车最大通过量的提升比例增加4.5%.

关键词: 交通工程, 交通设计, 线性规划, 连续流交叉口, 左转非机动车