Changeable message signs (CMSs) and dynamic speed displays (DSDs) for speed management applications have been deployed to address multiple situations. These have often been reported to produce beneficial effects, with most evidence coming from installations in work zones. The present paper reports on a controlled field test of a dynamic CMS in conjunction with radar based speed recording that is designed to produce conditional messages based upon the measured speed in an attempt to maximize impacts on driving speeds. The controlled test was followed by a demonstration along a public roadway, in which a temporary speed zone was created to determine if the experimental findings could be replicated in a real-world setting. The limited findings suggest that driving behaviors can be influenced by dynamic displays of conditional messages that are dependent upon different driving speeds.