There are many different roll cage designs depending on the application, hence different racing organizations have differing specifications and regulations, although most of these organizations harmonize their regulations with those of the FIA.
Ridge Rack’s roll cages help to stiffen the chassis, which is desirable in racing applications. Racing cages are typically either bolt-in or welded-in, with the former being easier and cheaper to fit while the latter is stronger.
A roll bar is a single bar behind the driver that provides moderate rollover protection. Due to the lack of a protective top, some modern convertibles utilize a strong windscreen frame acting as a roll bar. Also, a roll hoop may be placed behind both headrests (usually one on older cars), which is essentially a roll bar spanning the width of a passenger’s shoulders.