中文摘要：

针对中国城市道路中存在的交通拥挤现象，通过对城市道路路段上环形线圈采集到的交通流流量和占有率数据进行对比性分析和统计推导，从理论上论证了交通拥挤产生的原因;提出了交通拥挤现象出现与消散过程的相对增量判别准则，并利用给出的判别准则构造出相应的拥挤检测指标，给出了城市道路路段上交通拥挤的平均占有率自动检测算法;最后结合实际调查的数据，对算法的正确性进行了验证.

英文摘要：

Authors studied the basic relationship between flow and occupancy to propose a new criterion for identifying the onset of congestion in the road networks. With the criterion, authors derived some new guidelines for detecting congestion incidents, and could also measure off the traffic stream into four stages. Finally, with the research in above, authors advanced a new detection algorithm for road traffic congestion incidents which was validated by using the data from actual investigation.