HOUSTON -

People who are obese are more likely to die in car crashes then people of normal weight, a University of California Berkley research team said.

Their study which will be published in Tuesday's issue of Emergency Medicine Journal, used data from the National Highway Traffic Safety Administration.

Researchers focused on more than 6,800 drivers involved in crashes.  The looked specifically at those drivers who died within 30 days of their crash.

They found that clinically obese people with a body mass index (BMI) of between 30 and 35 were 20 percent more likely to die in a car crash.

Those who were considered morbidly obese -- with a BMI of 40 and above -- were 80 percent more likely to die in a crash.

Body mass index or BMI is the ratio of weight to height.  It is considered a good indicator of obesity.  A normal BMI is between 18 and 25.

The results did not change even after researchers accounted for factors that could have increased the risk of death in car crash including age, alcohol use, seat belt use, and whether or not air bags deployed.

Researchers said their findings may support the theory that cars, trucks, and other vehicles are not properly equipped for obese people.

A recent study found that obese drivers involved in crashes traveled father in their seats before their lap belts engaged compared to normal-weight drivers. 

That study suggested obese people had so much soft tissue or fat, that it prevented their seat belt from fitting snugly and reacting properly. 

Researchers said obese drivers may also be more likely to have underlying health problems, which the researchers called a "probable contributor" to their deaths.