The Dec. 22 crash on the Dan Ryan Expressway killed the 4-year-old from League City, who died from head trauma.
The Chicago Sun-Times reports ( http://bit.ly/1cTrqef) prosecutors say 46-year-old Franklin L. Jackson didn't notice the boy was missing until he pulled into a gas station to examine the vehicle's damage.
The preschooler wasn't wearing a seatbelt. He was found on an embankment.
Three other children—all under 2—weren't injured.
Jackson is charged with reckless homicide and aggravated driving under the influence. His attorney called the crash "a terrible tragedy" during a court appearance Wednesday.
Information from: Chicago Sun-Times, http://www.suntimes.com/index