There are several types of traffic control devices and different signage to be considered. ARX can help you best select which items are required and help in the ordering process. The standard use of traffic control devices is illustrated in OTM Book 7 for typical and common situations. It is difficult to illustrate detailed guidelines for all situations that may arise. Hills, curves, intersections, driveways, other physical features, and adverse weather conditions may require variations from the guidelines as illustrated.