Increased production, reduced labor, and a uniform surface are among the benefits of bridge deck paving machines. Called cylinder finishers or roller pavers by the manufacturers, the equipment has been available since the early 1960's. Newer slipform pavers can be better suited for some mainline paving of long sections, but deck pavers have earned a special role in bridge deck and special paving for construction and reconstruction projects. Bridge deck pavers spread, compact, and finish concrete. Both full-depth slabs and overlays can be finished. Similar or modified equipment can trim bases to final grade, then pave and finish flat or sloped surfaces for a variety of applications, such as runways, reservoir linings, spillways, and canals. When configured for deck paving, the machines consist of an open welded-steel frame supported by legs and wheeled bogies. Drive wheels on pipe rails move the paver along the length of the bridge. Flat slab, slope, and channel paving operations are similar, but one or both ends of the machine may be tread-mounted to run on the ground. This saves the labor costs of setting the support rails. A carriage suspended from the truss with travel and hold-down rollers moves from side to side, across the bridge.