The boy was riding on a martial arts studio's float at LibertyFest consisting of a pickup and a flatbed trailer. Near the end of the parade, witnesses say some part of the float may have struck the boy, knocking him down, Edmond Police Officer James Hamm said.
Hamm said the driver was unable to see what had happened behind him, and drove forward. The officer added that the father was not driving recklessly and did not violate traffic rules, and that it was an unfortunate accident.
Many people, including children -- some of whom knew the boy -- witnessed the accident. The boy was rushed to an area hospital where he was pronounced dead.
Hamm said the driver will not be charged in the accident, and police were giving the family space and planned to wait until Friday to formally question the father.
"I feel sorry for the family that came out here to celebrate the 4th of July," Hamm said. "Obviously, their world is turned upside down now."