Examination of the Factors Influencing the Clearance Time of Freeway Incidents

Traffic incidents are the primary cause of delay in urban settings, reducing capacity and creating risks for both motorists and incident response personnel. As incident duration increases, the risk of secondary incidents or crashes also becomes a problem. In response to these issues, many communities have initiated incident management programs aimed at detecting, responding to, and clearing incidents in order to restore freeways to full capacity as quickly and safely as possible. This study involved the development of fully parametric hazard duration models to examine those factors impacting the time required by the Michigan Department of Transportation's Freeway Courtesy Patrol to clear incidents that occurred on the freeway network in metropolitan Detroit. These models were developed using traffic flow data, roadway geometry information, and an extensive incident database. Four fully parametric hazard duration models are developed, each assuming a different underlying probability distribution for the hazard function. In general, each modeling framework provided similar results, though a log- logistic distribution is shown to provide a better fit for the incident clearance data in comparison to other distributions. Various factors were found to significantly affect incident clearance time, including the time of day and time of year at which the incident occurred, the geometric and traffic characteristics of the freeway segment, and the characteristics of the incident.

摘要为了解决日益严重的城市交通拥堵问题，近几十年来，研究人员在国内外高速公路和城市快速路上发现多种交通现象，并提出各种交通流模型对已发现的交通现象进行重现和解释，目的是为交通流控制与疏导提供了理论支持。本文首先对目前已发现的交通流现象，如通行能力陡降、滞后效应、走-停交通波和同步流现象进行介绍，然后从交通流模型中的速度、加速度和二阶加速度的宏观/微观，连续/离散表达式几方面介绍了现有的一些交通流模型，并对模型解释交通现象的能力进行综合性评述。