Refuge islands of many sizes and shapes can be introduced very quickly. As well as the pre-defined sizes, GuideSIGN Markings will allow the user to specify the dimensions of the island, and draw refuges as D, double-D, joined double-D, boat shaped, etc.

In addition, GuideSIGN Markings will draw islands suitable for junction arrangements where traffic lanes split. The dimensions required in the construction of these islands refer to the lengths to the intersection of the projected sides of the island, and there will therefore be some element of trial and error until the user is used to the method of working. The radii of the corners (ends) of the island can also be specified (default 0.45 m or 18 in.), as can the radius of any curved side of the island (default 10 m or 30 ft). The parameters setting the limits which can construct a sensible island have not been determined, so if it does not perform correctly, undo and try again with different values for one of the variables.