Sanford tried to turn from U.S. 1 onto Seminole Woods Boulevard and pulled out in front of another car, according to the Florida Highway Patrol.
Collins was a passenger in a pickup truck involved in a rollover crash on Dec. 10.
Two witnesses said that the boy had told them Dec. 7 he was planning to commit a shooting.
A student heard two boys talking on the school bus about committing a school shooting, according to a Sheriff's Office news release.
Brett Chambers was last seen the night of Dec. 12.
