Various exemplary methods and devices are provided for traversing a lumen, such as the gastrointestinal tract. The devices can include an elongate body having distally positioned tubing elements and proximally positioned control elements. The tubing elements are adapted for selective and independent radial expansion and contraction and longitudinal movement, such that movement of the tubing elements can drive the device through a lumen. In addition, the tubing elements can include a traction surface to reduce slippage.