Three Roses Club

Introduction
The Three Roses Club was a club of race car drivers who were shown racing predominantly at Danger Pass for several years. They are directly supported by Mr. Herring (緑川, Akai), Mr. Green (緑川, Midorikawa) and Mr. Black (黒沼, Kuronuma), who gave the Three Roses Club the order to kill Flash Marker.

Involvement in the Race for Revenge
After Speed is nearly killed by the X3 and Green is rammed off the road into a ravine, Inspector Detector begins to lead an investigation against the mysterious car. In the wreckage, Detector's men find a white card with "X3" written on it, and upon seeing the card Herring is visibly frightened. Despite clearly knowing something, he withholds information from Detector and denies that he knows what the letters mean, quickly leaving the office afterwards to go warn Mr. Black.

It's directly stated by Pops Racer that Herring, Green and Black were worried about the Three Roses Club being beaten by a new, young driver. Of course, that driver was Flash Marker and his custom made race car posed a threat to their ability to secure the win. With Marker standing in the way of their win, and their big payout, they decided to ram him off of Danger Pass, a wreck which cost Marker his life. Herring makes a phone call to Black telling him to not go out at night, as that's when Green was killed by the X3. Black is the president of Ocean Industries, which seems to be affiliated with the Three Roses Club. He also states that the night Herring called him was one that he had business on, so he had to go anyways. He ignores Herring's warning, which eventually ends with him being rammed off the road and into the ocean by the X3.

During the race at Danger Pass that Speed takes part in, the son of Flash Marker uses a remote controlled replica of the Melange while using his sister Lily Marker as a decoy driver so that nobody will suspect him.

During the race, he succeeds in killing two members of the Three Roses Club, but one of them escapes with their life thanks to Speed's interference. After the events of the race at Danger Pass, it's never revealed whether or not the Three Roses Club still exists. It's most likely that it was dissolved due to 2/3 of it's members being killed at Danger Pass. It's possible that the remaining member of the Three Roses continued to race with the support of Mr. Herring, but this is never confirmed in any canon source.

Trivia

 * Mr. Herring's full name is Red Herring, which is a reference to the phrase "Red Herring". It means "a clue or piece of information that is, or is intended to be, misleading or distracting". This could be a reference to Mr. Herring's denial of knowing the meaning of the letters on the card left by the Melange at the site of Green's death.
 * Mr. Black is the president of Ocean Industries, and winds up drowning to death after being rammed off the road by the Melange after likely being knocked out from blunt force trauma.
 * The numbers on the cars of the Three Roses Club are 7, 8, and 9. Their cars aren't based on any race car that has ever existed, but they do share a resemblance with the Bad to the Blade Hot Wheels car, which is a futuristic depiction of the IndyCar race cars.
 * Although it appears that Speed has killed off the last member of the Three Roses Club, this was actually a part of a popular Speed Racer parody created by YouTube user rexdoodle, titled "Speed Racer Goes Crazy".