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517 – Issues in Transportation Statistics
Why Is Road Safety Better Under Driving Impairment Due to Both Marijuana and Alcohol Than Each Separately? Data Analytics Answers, Ramalingam Shanmugam1, Ram c. Tripathi2 and Karan
Ramalingam Shanmugam
Texas State University
Ram Tripathi
University of Texas, San Antonio
Karan Singh
UT Health
Thought of encountering fatal road accidents due to impaired driver(s) scars public, regulating agencies, and mothers against drunk driving (MADD). For details, refer http://www.alcoholfacts.org/CrashCourseOnMADD.cfm . Motivated by the facts (see in Table 1) that the average number of fatal accidents caused by drivers impaired due to alcohol alone is worse than by drivers impaired due to marijuana alone. Surprisingly, a non-triviality appears. Why is it that the road safety is better when the drivers are impaired by both alcohol and marijuana? With an appropriate probability model for the incidences of fatal accidents, this article examines and explains the statistical reasons. This probability model is named confounded Poisson distribution (CPD). Statistical properties of CPD are identified and applied to analyze and demystify the uncertainty patterns using the fatal accidents that occurred in USA during 2013-2015 among the drivers in the age brackets 18 through 75+ years.