Loves Park police say it happened at the intersection of Mulford and Windsor Roads around 3:00 p.m.
A pickup truck was heading southbound on Mulford Road and a van belonging to Advanced Heating and Air Conditioning was traveling northbound on Mulford Road.
The van made a left turn onto Windsor Road and collided with the truck.
The passenger in the van was not wearing his seat belt and was ejected from the van. One witness says he believes the man was then run over.
Police say the victim was taken to Rockford Memorial Hospital where he is now in critical condition. There were no other injuries in the accident.
The driver of the van has been issued citations.