WASHINGTON - A new study from the National Highway Traffic Safety Administration has concluded that at least 42 percent of police officers killed in crashes over the past three decades were not wearing seat belts or other safety restraints, USA Today reported. 

The federal study analyzed 733 crashes from 1980 through 2008. Of the officers killed in vehicle crashes in the 1980s, just 28 percent were using a safety restraint at the time of the crash. In the 1990s the figure was 56 percent. But in more recent years the figure has dipped to 50 percent -- a disturbing trend. 

The study's findings indicate a serious problem, said Craig Floyd, chairman of the National Law Enforcement Officers Memorial Fund.

Some officers don't like to wear seatbelts because they feel they slow their movement in and out of the cars, Floyd said. Others say that the seatbelt straps can get tangled in utility or gun belts. Floyd's group is looking for new ways to promote officer safety on the road. 

According to the National Law Enforcement Officers Memorial Fund, there was a 37-percent overall increase in line-of-duty police deaths in 2010, reversing two straight years of decline. Traffic-related police fatalities rose from 51 in 2009 to 73 in 2010.

Some police departments are hoping to instill a cultural change that will result in more officers buckling up.