Driver distraction is a recognized cause of traffic accidents. Although the well-known guidelines for measuring distraction of secondary in-car tasks were published by the United States National Highway Traffic Safety Administration (NHTSA) in 2013, studies have raised concerns on the accuracy of the method defined in the guidelines, namely criticizing them for basing the diversity of the driver sample on driver age, and for inconsistent between-group results. In fact, it was recently discovered that the NHTSA driving simulator test is susceptible to rather fortuitous results when the participant sample is randomized. This suggests that the results of said test are highly dependent on the selected participants, rather than on the phenomenon being studied, for example, the effects of touch screen size on driver distraction. As an attempt to refine the current guidelines, we set out to study whether a previously proposed new testing method is as susceptible to the effects of participant randomization as the NHTSA method. This new testing method differs from the NHTSA method by two major accounts. First, the new method considers occlusion distance (i.e., how far a driver can drive with their vision covered) rather than age, and second, the new method considers driving in a more complex, and arguably, a more realistic environment than proposed in the NHTSA guidelines. Our results imply that the new method is less susceptible to sample randomization, and that occlusion distance appears a more robust criterion for driver sampling than merely driver age. Our results are applicable in further developing driver distraction guidelines and provide empirical evidence on the effect of individual differences in drivers’ glancing behavior.

驾驶员分心是交通事故的公认原因。尽管美国国家公路交通安全管理局（NHTSA）于2013年发布了用于衡量次要车载任务分散性的著名指南，但研究引起了人们对指南中定义方法的准确性的关注，即对其进行批评。因为驾驶员样本的多样性取决于驾驶员的年龄，并且各组之间的结果不一致。实际上，最近发现，当参与者样本随机化时，NHTSA驾驶模拟器测试很容易受到相当偶然的结果的影响。这表明所述测试的结果高度依赖于所选择的参与者，而不是所研究的现象，例如，触摸屏尺寸对驾驶员注意力分散的影响。为了完善当前指南，我们着手研究先前提出的新测试方法是否像NHTSA方法一样容易受到参与者随机化的影响。这种新的测试方法与NHTSA方法有两个主要区别。首先，新方法考虑的是遮挡距离（即驾驶员可以遮挡视线行驶的距离），而不是年龄；其次，新方法考虑的驾驶条件是比建议的更复杂，更真实的环境。 NHTSA指南。我们的结果表明，该新方法不易受到样本随机化的影响，并且闭塞距离对于驾驶员采样而言似乎比仅驾驶员年龄更可靠。