In a study conducted at the University of Buffalo, using data from the National Fatality Analysis Reporting System (FARS) and the National Highway Traffic Safety Administration (NHTSA), it was determined that 67 percent of normal weight drivers wear seatbelts while obese drivers do not.
Drivers considered to be overweight or obese are determined by their Body Mass Index (BMI). A person who has a BMI of 25 or more is considered obese by the World Health Organization, a person with a BMI of 30-35 is slightly obese, a BMI of 35-40 is moderately obese and a BMI of over 40 is considered morbidly obese. Considering that one-third of the US population is overweight and one-third is considered obese, this is of a great concern.
Obese drivers may find it more difficult to buckle up a standard seatbelt and therefore do not wear a seatbelt as often as normal weight drivers, so that means that the heavier the driver, the less likelihood that seatbelts were used.
Not buckling up is very dangerous because it delivers more force to the body much more quickly while also increasing the chances of being thrown about the car. Therefore, morbidly obese drivers have a 56 percent higher chance of death as a result of an automobile crash than normal weight drivers.