Hixson said only two of the seven people in the van were wearing seatbelts. The five who were not buckled in were ejected, but one survived.
"Unfortunately, so many in the van weren't wearing seatbelts, and some might have survived had they been wearing them," Hixson said. "We see it so many times where people can survive simply by having a seatbelt on."
The van was carrying a couple, their children and some aunts and uncles, he said. Killed were three men in their 40s, a teenage female and an adult female.