Identifying the Factors and Locations of Traffic Crash Severity of Dhaka
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A Thesis entitled Identifying the Factors and Locations of Traffic Crash Severity of Dhaka Metropolitan Area, Bangladesh, 2007-2011. by Panini Amin Chowdhury Submitted to the Graduate Faculty as partial fulfillment of the requirements for the Master of Arts Degree in Geography ________________________________________ Bhuiyan M. Alam, Committee Chair ________________________________________ Daniel J. Hammel, Committee Member ________________________________________ Yanqing Xu, Committee Member ________________________________________ Amanda C. Bryant-Friedrich, Ph.D. Dean, College of Graduate Studies The University of Toledo December 2018 i Copyright 2018, Panini Chowdhury This document is copyrighted material. Under copyright law, no parts of this document may be reproduced without the expressed permission of the author. ii An Abstract entitled Identifying the Factors and Locations of Traffic Crash Severity of Dhaka Metropolitan Area, Bangladesh, 2007-2011. by Panini Amin Chowdhury Submitted to the Graduate Faculty as partial fulfillment of the requirements for the Master of Arts Degree in Geography The University of Toledo December 2018 This study aims at exploring and analyzing different roadway, environmental and traffic factors that influence traffic crash severity and their spatial distributions in Dhaka city, Bangladesh. Using a multinomial logit model, the author regressed 12 roadways, environmental, and traffic factors on traffic crash severity. The study uses 2716 crash records that occurred over a period of 2007-2011. The study collected the data from Dhaka Metropolitan Police Department. The method of the study includes three steps. In the first step, this study presents a general descriptive statistic of the variables. The second step introduces the results of multinomial logistic regression model to help understand the impacts of different variables on traffic crash severity. Finally, this study developed a spatial analysis for the identifications of the vulnerable crash points and their relationship with the land use and population of those wards (Township equivalent). The study finds that 69% of the crashes were fatal. Seventy one percent of the crashes occurred at non- intersection locations, 63% occurred at uncontrolled or not prior supervised traffic intersections, 73% occurred on one-way or single direction roads, and 80% took place at iii road segments with presence of a road divider. The study also found pedestrian (60%) and rear-end (25%) collisions to be the most common types of collision. Weather and daylight conditions do not play significant role on reducing crashes. The author also finds that 96% of the crashes took place on straight roads, of which 67% occurred on the national highways. The majority (98%) of the crashes took place on roads that were not in poor condition. The most crash-prone period of the year is shown to be March–June. Variance Inflation Factors (VIF) and correlation coefficients were performed to test if there was multicollinearity among the explanatory variables. The overall model is statistically significant with the log likelihood value of 1044.67 and pseudo r-squared value of .37. The no intersection or general road segments and 3-way intersection points are more susceptible to fatal crashes than extensive injuries. Police controlled intersections have a positive impact in reducing crashes. Pedestrian, rear end and head-on collisions are found to be the most significant collision type. One-way roads are more vulnerable to crashes. Road dividers have a positive impact on crash reduction. Night time is more vulnerable to fatal crashes while extensive or minor injuries are more common during day time. National and regional highways are more vulnerable to crashes than the city or feeder roads. Speed breakers have an impact on reducing the fatal crashes. From the spatial hotspot analysis, it is found that there is no significant cold spot in the whole DMA with respect to traffic crashes. Crash points are highly clustered. The north, east and south side of the metropolitan area are more vulnerable to road traffic crashes than the western part of the city. Wards with moderate-high population and mixed (residential-commercial, commercial- industrial) land use are more crash-prone than the dedicated residential or educational zones. iv Acknowledgements I am deeply grateful to my supervisor Dr. Bhuiyan M. Alam for his dedication and support throughout my research. This study would not have been possible without his guidance and help. This journey allows me to learn his ways of thinking and working and I am often impressed by his logical thoughts and wise solutions to difficult research questions. I also want to thank him for his useful comments and remarks on my writings and formats. I am honored to have Dr. Daniel J. Hammel and Dr. Yanqing Xu to be my dissertation committee members. I also want to thank Dr. Bayes Ahmed for sharing his database with me. I am thankful to my father and sister because without their continuous support, it would not be possible. I thank you all for your time and effort for my dissertation. Finally, I would like to thank my Beautiful wife “Daizy” for making my life and my works more eloquent. Thank you, my “Wonder Woman.” v Table of Content Abstract .............................................................................. Error! Bookmark not defined. Acknowledgement ...............................................................................................................v Introduction ..........................................................................................................................1 1.1 Background of the Study .......................................................................................1 1.2 Rationale of the Study ...........................................................................................5 1.3 Goal & Objective ..................................................................................................6 1.5 Limitation of the Study ..............................................................................................6 Literature Review.................................................................................................................8 Research Design & Data Management ..............................................................................16 3.1 Introduction ..............................................................................................................16 3.2 Background of the study ..........................................................................................16 3.3 Study Area ................................................................................................................17 3.4 Data Collection & Processing ..................................................................................19 3.4.1 Crash Data Collection (2007-2011) ...................................................................19 3.4.2 Data Classification .............................................................................................20 3.4.3 Spatial Data Collection ......................................................................................24 3.5 Techniques of Research ...........................................................................................26 3.5.1 Multinomial Logistic Regression Analysis .......................................................26 vi 3.5.2 Predicting & Outcome Variables .......................................................................28 3.5.3 Network-Based Kernel Density Estimation ......................................................29 3.5.4 Optimized Hotspot Analysis ..............................................................................31 3.5.5 Spatial Autocorrelation Analysis .......................................................................32 Results ................................................................................................................................34 4.1 Descriptive Statistics ................................................................................................34 4.1.1 Road Crashes in the Major Cities of Bangladesh ..............................................34 4.1.2 Crash Trend of Dhaka Metropolitan Area.............................................................35 4.1.3 Crash Statistics of Dhaka Metropolitan Area 2007-2011 ..................................36 4.1.4 Crash Severity....................................................................................................38 4.1.5 Intersection Type of the Crashes .......................................................................39 4.1.6 Traffic control system of the Crash Locations ..................................................40 4.1.7 Collision Type ...................................................................................................41 4.1.8 Traffic Flow Direction in the Location of the Crashes ......................................42 4.1.9 Impact of Road Divider .....................................................................................43 4.1.10 Weather Condition of the Crash Time .............................................................44 4.1.11 Lighting Condition ..........................................................................................45 4.1.12 Road Geometry ................................................................................................46 4.1.13 Temporal Trend of the Crashes .......................................................................47