中文摘要：

针对信号控制环形交叉口这一特殊的控制对象，运用理论解析结合计算机仿真检验的方法，分别给出环形交叉口直行和左转的延误计算模型；并在此基础上提出了一种以交叉口车均延误最小为目标，适合于在非饱和状态下采用多进口道放行协同环道控制环形交叉口的最佳周期值计算方法。最后通过模拟试验和实例分析对模型的适用性进行了检验。结果表明：该模型有较高的精度和可靠性，为求解环形交叉口信号控制最佳周期提供了一种有效的新算法。

英文摘要：

Aimed at the roundabout with signal control which is a special control object, using the theory analysis and computer simulation test, authors established the delaying calculation model of through running and left-turning vehicle of roundabout. Then, authors derived the optimal cycle calculation method based on the minimum delay, which was suitable for the multi-approach going coordinated with roundabout control. At last, by simulation experiment and case study, the adaptability of the proposed model was checked out. Results show that the suggested model can provide a new method for optimal cycle of signal control at roundabout.