This study aims to estimate and compare the parameters of some univariate and bivariate count models to identify the factors affecting the number of mortality and the number of injured in road accidents. The accident data used in this study are related to Kermanshah province in march2020 to march2021. Accidents areas were divided into 125 areas based on density characteristics. In a one-year period, 3090 accidents happened on the suburban roads of Kermanshah province, which resulted in 398 deaths and 4805 injuries. Accident information, including longitude and latitude of accident location, type of accident (fatal and injury), number of deaths, number of injuries, accident type, the reason of the accident, and the kind of accident were all included as population-level variables in the regression models. We investigated four frequently used bivariate count regression models for accident data in the literature. In bivariate analysis, except for the DNM model, there is a reasonable decrease in the AIC measures of the saturated model compared to the reduced model for the other three models. For the injury models, MSE is lowest, respectively for DIBP (137.87), BNB (289.46), BP (412.36) and DNM (3640.89) models. These results are also established for death models. But, in univariate analysis, only injury models almost present reasonable results. Our findings show that the IDBP model is better suitable for evaluating accident datasets than other models. Motorcycle accidents, pedestrian accidents, left turn deviance, and dangerous speeding were all significant variables in the IDBP death model, and these parameters were linked to accident mortality.

中文翻译：

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伊朗道路交通事故伤亡分析：双变量回归方法

本研究旨在估计和比较一些单变量和双变量计数模型的参数，以确定影响道路事故死亡率和受伤人数的因素。本研究中使用的事故数据与 2020 年 3 月至 2021 年 3 月的克尔曼沙省有关。根据密度特征将事故区域划分为125个区域。一年时间里，克尔曼沙阿省郊区道路发生交通事故3090起，造成398人死亡4805人受伤。事故信息，包括事故地点的经纬度、事故类型（致命和受伤）、死亡人数、受伤人数、事故类型、事故原因和事故类型，均作为人口水平变量在回归模型中。我们调查了文献中四种常用的事故数据双变量计数回归模型。在双变量分析中，除 DNM 模型外，与其他三个模型的简化模型相比，饱和模型的 AIC 测量值有合理的降低。对于损伤模型，MSE 最低，分别为 DIBP (137.87)、BNB (289.46)、BP (412.36) 和 DNM (3640.89) 模型。这些结果也适用于死亡模型。但是，在单变量分析中，只有损伤模型几乎呈现出合理的结果。我们的研究结果表明，IDBP 模型比其他模型更适合评估事故数据集。摩托车事故、行人事故、左转偏差和危险超速都是 IDBP 死亡模型中的重要变量，这些参数与事故死亡率相关。