A Mokena man was sentenced Friday to 12 years in prison for a 2011 drunken driving collision that killed a 72-year-old woman and her 92-year-old mother and injured a special-needs adult, Will County State’s Attorney James Glasgow said.

Joseph E. Slattery, 27, 20016 Lakeview Way, was drunk while driving his Chevrolet Cavalier about 8 p.m. Aug. 28, 2011, on LaGrange Road just north of Wilmington-Peotone Road when he veered over the center line and struck another vehicle with three occupants, Glasgow said in a press release.

Margaret Simons, 72, the driver of the vehicle, was pronounced dead at the scene, while her mother and passenger, Suzanne Thompson, 92, suffered severe bilateral pelvic fractures and died three hours later at St. Mary’s Hospital in Kankakee.

Another passenger and a special-needs adult, Ralph Simons, then 42, suffered a fractured left hip and left hand and was hospitalized for 13 days.

Slattery, who had a blood-alcohol level of .092 and tested positive for opiates, admitted to taking a friend’s Vicodin two nights before, according to Glasgow.

At the time of the crash, Slattery was driving with his girlfriend and their 18-month-old son, who was treated at St. Mary’s for a facial wound. The mother appeared unharmed. Police found an empty carton of Bud Light in the vehicle, but no actual containers in the car, Glasgow said in the press release.

Circuit Judge Amy Bertani-Tomczak imposed the sentence after hearing emotional statements from the family of the victims, according to the press release.

“Joseph Slattery’s decision to drive drunk showed a callous disregard for the safety of other motorists, and his actions cost two women their lives,” Glasgow said. “He should spend his time in prison contemplating the horrific results of his crime.”

Glasgow credited prosecutors Frank Byers and Tom Slazyk for securing the conviction and sentence, along with Illinois State Police Trooper Sam Heenan, who was the officer on the scene, and Sgt. Dustin Geier, who performed the accident reconstruction component of the investigation.