Michigan State Police say 20 drivers have been cited in the deadly Jan. 17 pile-ups on I-94 in Van Buren County, Fox 17 reports. 

The multiple vehicle crash caused I-94 to close in both directions near Hartford and Watervliet for several hours.

The first accident occurred on eastbound I-94 and involved nine vehicles. Two semi trucks then collided, causing a pile-up of more than 40 vehicles.

Shortly after, another accident involving 12 vehicles occurred in the westbound lane.

A 78-year-old Northville woman, Carol Greisemer, was killed in the eastbound crash. Her son, 54-year-old Andrew Griesman, later died of injuries incurred at the accident.

Police have cited fifteen drivers in the eastbound crash and five in the westbound crash for driving too fast in white-out conditions.