Police said Michael Jerome Walker shoved his girlfriend's 5-year-old son into a lane of traffic on Highway 121 late Saturday night.
Grapevine police say a domestic dispute between a couple in a car ended with a little boy being pushed into oncoming highway traffic.
While police say domestic disturbances in vehicles are common, Saturday night's incident stunned officers.
Police said a Lewisville woman got into a heated argument with her boyfriend on southbound State Highway 121, just north of the merger with State Highway 114 and the north airport entrance gate, while driving him and her 5-year-old son to Fort Worth at about 11 p.m.
“At one point, he threatened to harm her and actually hit her in the side of the head,” Lt. Todd Dearing said.
The woman stopped her car right in the middle of traffic and tried to flag down help, police said.
Police said the boyfriend, Michael Jerome Walker, then turned his attention to her son.
"He said, 'I'm about to put mommy to sleep and she's not going to wake up,'” Dearing said.
Witnesses said Walker lifted the child up in the air and shook him violently.
Several drivers called 911.
“The guy has some woman's baby, and the baby got thrown out onto the middle of the highway,” one caller told 911.
Police said Walker shoved the child into oncoming traffic after the boy shook free of him.
Seconds later, a van slammed into the mother's car, turning it sideways.
No one was injured.
Walker remained jailed Monday in Grapevine on three counts of assault, endangering a child and making threats.
Police said it is a miracle no one was killed because the incident occurred at night, when cars whizzed by at speeds of 80 mph in the dark.
"Everybody was very, very lucky that no one got more seriously hurt,” Dearing said.