Abstract: A wheeled vehicle provided with three individually driven wheels rotatable on horizontal axes. The wheels are disposed at the corners of a triangle. The periphery of each wheel is defined by a plurality of rollers rotatable on respective axes which are each at an angle to the axis of the respective wheel. The axes of three rollers, one for each wheel, when each such roller is in its lowermost position, form a triangle. Each roller axis may be at right angles or perpendicular to, or at 45 degrees to, or at some other acute angle to the respective wheel axis, and the triangle may be an equilateral triangle in a typical embodiment of the invention.According to a preferred embodiment of the invention, no two of the wheel axes are aligned or parallel to each other. In a typical construction, the wheels are at the corners of an equilateral triangle and the wheel axes intersect at the center of this triangle.