Investigators are trying to determine why a car stopped on a Kansas City interstate, leading to an accident that left five people dead.

A woman from Warrensburg, three of her young children and a family friend died in the crash Saturday on Interstate 435. Police say the woman's car stopped in a lane of traffic and was hit from behind by an 18-wheel tractor-trailer, killing everyone in the car.

The victims were identified as the car's driver, 24-year-old Shante Hopkins; her two daughters, 2-year-old Ja Riah Hutchinson and 1-year-old Nijah Hutchinson; her 7-month-old son, Tay Shawn Hutchinson and a family friend, 17-year-old Dominique Johnson of Kansas City.

Investigators plan to examine the car Monday to determine if mechanical problems caused it to stop in traffic.