I would simply use the term "Cycles and off-road vehicles" as the term for the paper, especially if you need to include ATVS also. It is probably the most commonly used phrase , to include how its used in statutes and laws. Some of the terms on here that have been mentioned are correct and all, but I think they are too technical, and not really practical sounding. You want to also keep the readers attention and make the paper reach the avarage person. the phrase "Cycles and off-road vehicles' would sound more practical to me than 1 track vehicle, and conveyance if I was not avid on those kinds of vehicles. Thats just my opinion.