In most US states, a license is not needed to drive almost any vehicle (including cars) on private property - parental permission or supervision may be required. On public roads, driving farm equipment (like tractors) is permissable without a license, at ages below 15 in some cases. Also, many underpowered (less than 5 horsepower) vehicles do not require a license as long as they are driven or ridden on public roadways that allow it.