We examine the relationship between snow events and traffic crashes in four counties in northern Indiana across three consecutive winters, totaling 15,515 crashes. We compare daily crash occurrence and frequency with daily snowfall observations at the nearby South Bend International Airport. Then, we analyze radar and surface meteorological observations during the 3,801 crashes in the data set that were reported during “snow” or “blowing sand/soil/snow” conditions. Results show that daily crash totals increase by about 3.1 percent per centimeter of daily snowfall. Over half of crashes reported during snow or blowing sand/soil/snow conditions intersected very weak base reflectivity values from the nearby IWX radar, indicating snowfall was either very light or absent. Comparison of two different crash samples reveals that temporal clustering is most common among crashes intersecting reflectivity values >15.0 dBZ during midday and afternoon hours. Thus, we find that 15.0 dBZ is the approximate reflectivity value representing the intensity at which snowfall becomes notably more hazardous to traffic during high volumes. Finally, about a third of the crashes reported during blowing sand/soil/snow conditions that did not intersect substantial radar reflectivity occurred during meteorological observations consistent with blowing snow according to prior research.

我们研究了印第安纳州北部四个县连续三个冬季的雪灾与交通事故之间的关系，总共发生了 15,515 起车祸。我们将每日坠机事件和频率与附近南本德国际机场的每日降雪观测值进行比较。然后，我们分析了数据集中在“雪”或“吹沙/土壤/雪”条件下报告的 3,801 起坠机事件期间的雷达和地面气象观测。结果显示，每日降雪量每增加一厘米，每日事故总数就会增加约 3.1%。在下雪或吹沙/土壤/雪况期间报告的事故中，超过一半与附近 IWX​​ 雷达的非常弱的基础反射率值相交，表明降雪非常少或没有。Z在中午和下午时间。因此，我们发现 15.0 dB Z是近似的反射率值，代表在高流量期间降雪对交通变得更加危险的强度。最后，根据先前的研究，在与大量雷达反射率不相交的吹沙/土壤/雪条件下报告的坠机事故中，约有三分之一发生在与吹雪一致的气象观测期间。