is the kid on a team? no team wants a rep for having dangerous riders on it. it's embarrassing and paints a bad picture of the entire squad. contact the team and tell them specifically in a well worded email that <name the rider> has developed a reputation throughout the <category #> of being a sloppy and dangerous rider. tell them that various folks within the peloton have addressed this verbally with <again name the rider> and he has responded with foul language and <describe the situation above>. tell them that you've identified this to the USAC official and will continue to do so, and cordially ask that the team discuss this with the rider to assist him with his development and nip the dangerous riding and behavior in the bud.