The drive module comprises a single wheel (14) driven direct by pedals (12) and fitted with a freewheel. The wheel is rigidly mounted on a frame (16,17) and a seat (18) is also fixed on the frame. A coupling is provided for the articulated coupling of a further drive module or a driveless module (30) while a steering device is provided with a coupling member (42) for a further drive module or driveless module. The coupling can be provided at the back of the drive module. A further coupling for a drive module is provided at the front. The coupling can include coupling elements for power supply or brakes. The steering device has one, preferably two "Bowden" (RTM) cables.
