SPRINGFIELD, Mo. (AP) — A southwest Missouri father who lost three of his children in a traffic accident last July has filed a wrongful death lawsuit against the mother of his children, who he says was speeding, and a tractor-trailer driver.

The Springfield News-Leader reports that Ionel Dobos alleges in the suit filed this month that the driver of the rig failed to signal when he re-entered Interstate 44 after having been parked beside the road near Springfield.

According to Dobos’ lawsuit, Claudia Dobos was negligent and speeding when her van hit the front of the rig then slammed into the guardrail. The impact tore a large hole in the side of the van. Six-year-old Julia Dobos, 7-year-old Angelina Dobos and 8-year-old Olivia Dobos were ejected from the vehicle and killed. Five of their other children also were in the van, and some of them suffered significant injuries.

The News-Leader was unable to reach attorneys for Claudia and Ionel Dobos. The report did not explain the status of their relationship. No criminal charges have been filed in the crash.

The lawsuit also named companies that were in charge of employing and supervising the rig’s driver. The suit alleged that he violated rules that prohibit truckers from driving more than 70 hours in an eight-day period and eight-straight hours in a day.