Secondary crashes are crashes that occur as a result of the nonrecurrent congestion originating from primary crashes, and always have a greater impact on safety and traffic than a single crash. A better understanding of secondary crashes would benefit traffic incident management, and this requires accurate identification of secondary crashes. This study explores using crowdsourced Waze user reports to identify secondary crashes. A network-based clustering algorithm is proposed to extract the primary crash cluster, including all user reports originating from the primary crash, and any crash that occurred within the cluster would be a secondary crash. This method works as a filter to select accurate primary–secondary relationships, thus precisely identifying secondary crashes. A case study is performed with crashes occurring from June to December 2019 on a 30-mi stretch of I-40 in Knoxville, TN. A static threshold method (crash duration and 10 mi) was used to preselect the potential primary–secondary crash pairs, and 75 out of 708 crashes were identified as potential secondary crashes. Based on the preselected primary–secondary crash pairs, 17 secondary crashes were obtained with the proposed method and the results were compared with one of the commonly used methods, the speed contour plot method. Though the proposed method captured fewer secondary crashes, it did identify several secondary crashes that could not be observed with the speed contour plot method. The results showed the applicability of the method and the potential of crowdsourced Waze user reports in secondary crash identification.

次要崩溃是由于主要崩溃引起的非经常性拥塞而导致的崩溃，并且比单个崩溃对安全和流量的影响总是更大。更好地理解次要崩溃将有益于交通事故管理，并且这需要准确地识别次要崩溃。这项研究探索了使用众包的位智用户报告来识别二次崩溃。提出了一种基于网络的聚类算法来提取主要崩溃群集，包括源自主要崩溃的所有用户报告，并且在群集内发生的任何崩溃都将是次要崩溃。该方法用作筛选器，以选择准确的主要-次要关系，从而精确地识别次要碰撞。案例研究是从2019年6月至2019年12月在田纳西州诺克斯维尔30米长的I-40事故中发生的。静态阈值方法（碰撞持续时间和10英里）用于预先选择潜在的主要-次要碰撞对，在708次碰撞中，有75次被识别为潜在的次要碰撞。根据预选的一次-次要碰撞对，使用所提出的方法获得了17次次要的碰撞，并将结果与​​一种常用的速度轮廓图方法进行了比较。尽管所提出的方法捕​​获了较少的二次碰撞，但它确实识别出了一些等速线图方法无法观察到的二次碰撞。结果表明该方法的适用性以及众包的Waze用户报告在二次碰撞识别中的潜力。