A new study has found that obese drivers are more likely to die in car crashes because their seat belts do not tighten as quickly.
The mechanics of what happens are that in a car crash obese drivers are propelled forward, but their extra soft body tissue stops seat belts from tightening immediately against the pelvis.
The authors of the study from the University of California and the University of West Virginia published their findings online on Monday in the BMJ Group’s Emergency Medicine Journal.
The researchers examined data from the US Fatality Analysis Reporting System from 1996 to 2008. In that period, 57,491 collisions in the nation were submitted, said USA Today.
According to the study, those who were most overweight — World Health Organisation grades obesity category III (a BMI above 40) — were 80 percent more likely to die in an accident than drivers of a healthy and moderate weight.
Those in category II (a BMI between 35 and 39.99) were 51 percent more likely to be killed in a crash, while those in the lower category I (a BMI between 30 and 34.99) were calculated at a 21 percent risk.
Scientists said obese women were also found to be at a greater risk than men, while those in obesity category III were almost twice as likely to die on the road than their male equivalents.
In addition, analysis of more than 3,403 pairs of drivers showed underweight men were more likely to die in a collision than motorists of a healthy weight.
“Findings from this study suggest that obese vehicle drivers are more likely to die from traffic collision-related injuries than non-obese occupants involved in the same collision.
“Obese cadavers had significantly more forward movement away from the vehicle seat before the seat belt engaged the pelvis owing to additional soft tissue that prevents the belt from fitting close to the pelvis when the cadavers were in the driving position.
“The additional forward motion by cadavers was seen for the abdomen and lower extremities.”
The study said that, while obese drivers may be more likely to have underlying health problems, which could also put them at higher risk in a car accident, car design may have to change to protect overweight drivers, Sky News reports.
“The ability of passenger vehicles to protect overweight or obese occupants may have increasingly important public health implications, given the continuing obesity epidemic in the USA,” the authors said in a statement.
More than a third of US adults — 35.7 percent— are obese, according to the Centers for Disease Control and Prevention, while 16.9 percent of US children and adolescents are obese, USA Today notes.