ROADrule USATONS is a quick reference tool that identifies the most common U.S. aids to navigation, rules of the road, and maneuvering and warning signals for U.S. waters. ROADrule takes a large amount of complex information and makes it easy to understand. Whether in a classroom or at the helm, critical decisions can be made quickly and with confidence with the aid of ROADrule. Its design is similar to a slide-rule. (Versions of ROADrule are also available for European Inland Canals (291) and International Waters (292).