• International Journal of Highway Engineering
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• v.12 no.2
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• pp.43-49
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• 2010

This study deals with the traffic accident of the Cheongju arterial link sections. The purpose of the study is to develop the traffic accident model. In pursuing the above, this study gives particular attentions to developing the ZAM(zero-altered model) model using the accident data of arterial roads devided by 322 small link sections. The main results analyzed by ZIP(zero inflated Poisson model) and ZINB(zero inflated negative binomial model) which are the methods of ZAM, are as follows. First, the evaluation of various developed models by the Vuong statistic and t statistic for overdispersion parameter ${\alpha}$ shows that ZINB is analyzed to be optimal among Poisson, NB, ZIP(zero-inflated Poisson) and ZINB regression models. Second, ZINB is evaluated to be statistically significant in view of t, ${\rho}$ and ${\rho}^2$ (0.63) values compared to other models. Finally, the accident factors of ZINB models are developed to be the traffic volume(ADT), number of entry/exit and length of median. The traffic volume(ADT) and the number of entry/exit are evaluated to be the '+' factors and the length of median to be '-' factor of the accident.

• International Journal of Highway Engineering
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• v.14 no.2
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• pp.101-108
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• 2012

This study deals with the traffic accidents of circular intersections in Korea. The goal of this study is to develop the traffic accident models using ZAM. The main results are as follows. First, in the case of 'violating the operational method of intersection', ZINB(zero-inflatednegative binomial) models were analyzed to be the best fit to the data. Second, in the case of' no maintaining the safe distance', ZINB models were also analyzed to be the best fit to the data. Finally, such the common variables as traffic volume and width of circular roadway were selected as the independent variables. The more traffic volume and the less width of circulatory roadway were evaluated to make the more accidents. Such the specific variables as the number of approach lanes and speed reduction facilities were selected as the explanatory variables. The more approach lanes and the less speed reduction facilities were evaluated to give the more accidents. This study might be expected to give some implications to the accident research on the circular intersections.

• Journal of Korean Society of Transportation
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• v.29 no.6
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• pp.67-74
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• 2011

This study deals with the traffic accidents data from the Korean rotaries (circular intersections) to verify their characteristics affected by different vehicle types. This paper categorized the data into three groups based on vehicle types, and developed a set of accident models. The paper proposed two ZIP models and one negative binomial model through a statistical analysis for three vehicle types: automobile, truck and van, and others. The differences among those models were then statistically compared.