Environmental factors affecting the frequency of traffic accidents leading to death in 22 districts of Tehran during 2014–2016


1 Safety Promotion and Injury Prevention Research Center, Department of Epidemiology, School of Public Health and Safety, Shahid Beheshti University of Medical Sciences, Tehran, Iran

2 Occupational Health and Safety Research Center, Hamadan University of Medical Sciences, Hamadan, Iran

3 Safety Promotion and Injury Prevention Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran

4 Social Determinants of Health Research Center, Research Institute for Health Development, Kurdistan University of Medical Sciences, Sanandaj, Iran

5 Accident Department, Traffic Police of Tehran, Iran

6 Department of Biostatistics, Faculty of Paramedical Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran


Background: In many developed and developing countries, a significant proportion of deaths from road traffic accidents occur in the passages within cities. Considering the importance of this issue, this study was conducted to determine the environmental factors affecting the frequency of deaths in 22 areas of Tehran. Materials and Methods: In this study, the statistical population consisted of traumatic traffic incidents during the period of 2014–2016, all of which were studied. The data necessary for conducting the study were extracted from the traffic police databases, Tehran Municipality, and the Statistics Center of Iran. In order to analyze the role of regional and environmental factors in the frequency of traffic accidents related to pedestrians in geographic units (22 districts of Tehran), the Poisson regression and geographically weighted regression models were used. The likelihood ratio test was used to compare the models. The goodness-of-fit of models was evaluated using R2, Bayesian information criterion, and Akaike's information criterion statistics. Results: In this study, 519 incidents were studied, 175 of which (33.7%) were related to motorcyclists, 174 (33.5%) related to automobile drivers, and 170 (32.8%) pedestrians. The frequency distribution of the incidents studied varied in Tehran's 22 districts. The incidence of accidents in the central regions of Tehran was lower, while marginal areas located in the north, south, east, and west of Tehran had the highest frequency of fatal accidents. The both final Bayesian Poisson and GWR models showed that the relationship between the length of highways and educational land used with dependent variable was statistically significant. Conclusion: Various demographic and environmental variables play a role in determining the distribution pattern of these types of events. Through regional planning, proper traffic management, controlling environmental risk factors, and training people the pedestrian safety in Tehran can be improved.


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