right now, I'm working on a game called mud runner for Roblox and what I want is, when i drive the car fast on mud, sand, or grass, the trail will activate and add a trail from whatever ground you are on, onto the back of the tires, and the bigger it is, depends on how fast you are going. if anyone can help me with it, please reply, I really want to make my game as realistic and full of content as possible when its done :D