Application of the Poisson-Tweedie distribution in analyzing crash frequency data

2020 ◽  
Vol 137 ◽  
pp. 105456 ◽  
Author(s):  
Dibakar Saha ◽  
Priyanka Alluri ◽  
Eric Dumbaugh ◽  
Albert Gan
Author(s):  
Huiying Wen ◽  
Xuan Zhang ◽  
Qiang Zeng ◽  
Jaeyoung Lee ◽  
Quan Yuan

This study attempts to investigate spatial autocorrelation and spillover effects in micro traffic safety analysis. To achieve the objective, a Poisson-based count regression with consideration of these spatial effects is proposed for modeling crash frequency on freeway segments. In the proposed hybrid model, the spatial autocorrelation and the spillover effects are formulated as the conditional autoregressive (CAR) prior and the exogenous variables of adjacent segments, respectively. The proposed model is demonstrated and compared to the models with only one kind of spatial effect, using one-year crash data collected from Kaiyang Freeway, China. The results of Bayesian estimation conducted in WinBUGS show that significant spatial autocorrelation and spillover effects simultaneously exist in the freeway crash-frequency data. The lower value of deviance information criterion (DIC) and more significant exogenous variables for the hybrid model compared to the other alternatives, indicate the strength of accounting for both spatial autocorrelation and spillover effects on improving model fit and identifying crash contributing factors. Moreover, the model results highlight the importance of daily vehicle kilometers traveled, and horizontal and vertical alignments of targeted segments and adjacent segments on freeway crash occurrences.


2019 ◽  
Vol 1 (1) ◽  
pp. 15-21
Author(s):  
Rada Puspita ◽  
Haves Ashan ◽  
Fidiariani Sjaaf

Vision impairment is estimated to affect 285 million people in the world, where 16-20% experience blindness, from the number of blindness suffered at the age of 40-50 years. Cataract seninis is all lens opacities that are found in old age that is above 40 years. The purpose of identifying and collecting frequency data Profile of Senilis cataract patients at the age of 40 years and above at RSI Siti Rahmah Padang in 2017. The research method is descriptive type of research, this study data taken is secondary data, In this study data was taken from the Medical Record at RSI Siti Rahmah Padang. When the study was conducted in February-August 2018, the population of this study were all cataract patients at the age of 40 years and above at RSI Siti Rahmah Padang in 2017 with 80 samples. Data analysis is univariate presented in the form of a frequency distribution table. Results From 80 respondents as many as 40 people (50%) were in the age range of 60-69 years, as many as 42 people (52.5%) patients were male, as many as 31 people (38.8%) patients with high school education and 35 people (43.8%) patients work as private companies. Conclusion In general, most patients are at the age of 60-69 years, the most sex is men, the highest education is high school and most patients are private.


2017 ◽  
Vol 26 (1) ◽  
pp. 60-75 ◽  
Author(s):  
Krystelle Shaughnessy ◽  
Miranda Fudge ◽  
E. Sandra Byers

Sign in / Sign up

Export Citation Format

Share Document