Distracted driving is among the leading causes of motor vehicle crashes in the United States, though the magnitude of this problem is difficult to quantify given limitations of police-reported crash data. This study leveraged data from the second Strategic Highway Research Program Naturalistic Driving Study to gain important insights into the risks posed by driver distraction on both freeways and two-lane highways. More than 50 types of secondary tasks were aggregated into ten distraction type categories and mixed-effects logistic regression models were estimated to discern how the risks of near-crash events varied by distraction type while controlling for the effects of driver, roadway, and traffic characteristics. In general, the types of distractions that created the most pronounced risks were those that introduced a combination of cognitive, visual, and manual distractions. For example, drivers who used cell phones were subject to higher risks and these risks tended to be most pronounced when both visual and manual distractions were involved. Likewise, risks tended to be highest when drivers reached for other objects inside the vehicle, engaged in personal hygiene-related activities, or focused on activities occurring outside of the driving environment. Although the same factors tended to increase near-crash risk on both types of facilities, the impacts of several factors tended to be more pronounced on two-lane highways where interaction with other vehicles occurred more frequently. From a policy standpoint, the results of this study provide further motivation for more aggressive legislation and enforcement of distracted driving.

分心驾驶是美国机动车事故的主要原因之一，尽管鉴于警方报告的事故数据的局限性，这个问题的严重程度难以量化。这项研究利用了第二个战略公路研究计划自然驾驶研究的数据，以深入了解高速公路和双车道高速公路上驾驶员分心所带来的风险。将 50 多种次要任务汇总到十个分心类型类别中，并估计了混合效应逻辑回归模型，以在控制驾驶员、道路和交通特征的影响的同时，辨别近乎碰撞事件的风险如何因分心类型而变化. 一般来说，造成最明显风险的干扰类型是那些引入了认知、视觉和手动干扰。例如，使用手机的司机面临更高的风险，当涉及视觉和手动分心时，这些风险往往最为明显。同样，当驾驶员伸手去拿车内的其他物体、从事与个人卫生相关的活动或专注于驾驶环境之外的活动时，风险往往最高。虽然相同的因素往往会增加两种类型设施的近乎碰撞风险，但几个因素的影响往往在双车道高速公路上更加明显，因为与其他车辆的交互发生得更频繁。从政策的角度来看，这项研究的结果为更积极的立法和分心驾驶的执法提供了进一步的动力。使用手机的司机面临更高的风险，当涉及视觉和人工分心时，这些风险往往最为明显。同样，当驾驶员伸手去拿车内的其他物体、从事与个人卫生相关的活动或专注于驾驶环境之外的活动时，风险往往最高。虽然相同的因素往往会增加两种类型设施的近乎碰撞风险，但几个因素的影响往往在双车道高速公路上更加明显，因为与其他车辆的交互发生得更频繁。从政策的角度来看，这项研究的结果为更积极的立法和分心驾驶的执法提供了进一步的动力。使用手机的司机面临更高的风险，当涉及视觉和人工分心时，这些风险往往最为明显。同样，当驾驶员伸手去拿车内的其他物体、从事与个人卫生相关的活动或专注于驾驶环境之外的活动时，风险往往最高。虽然相同的因素往往会增加两种类型设施的近乎碰撞风险，但几个因素的影响往往在双车道高速公路上更加明显，因为与其他车辆的交互发生得更频繁。从政策的角度来看，这项研究的结果为更积极的立法和分心驾驶的执法提供了进一步的动力。