A wheelchair ramp is an incline plane installed in addition to or instead of stairs. Ramps permit wheelchair users, as well as people pushing strollers, carts, or other wheeled objects, to more easily access a building. Wheelchair ramps come in a number of varieties each intended for a different purpose. There are permanent, semi-permanent and portable. Permanent ramps are designed to be bolted or cemented in place. Semi-permanent ramps rest on top of the ground or cement pad and are commonly used for the short term. Portable ramps are lightweight, usually aluminum and typically fold for ease of transport.