Four-wheeled or quad all-terrain vehicles are generally considered to be easier to operate, safer and more stable at low speeds than three-wheeled ATVs. Quads are also the only current ATV configuration sold in the American market as of 2015, largely due to concerns about the safety of three-wheeled models.
The majority of major ATV manufacturers reached an agreement with the Consumer Product Safety Commission to cease production of three-wheeled ATV models in 1987 due to the high rate of injuries and fatalities associated with these vehicles. Though the ban technically ended in 1997, no major American or Japanese manufacturer produces a three-wheeled ATV. Some Chinese companies continue to produce three-wheeled designs, but Congress banned import of these vehicles into the United States in 2008.