Impediments to the Effective Use of Portable Variable Message Signs at Freeway Work Zones

Portable variable message signs have the ability to provide motorists with real-time information regarding changes in roadway traffic conditions and construction activities as well as providing motorists with information about the actions that should be taken due to these conditions. Because they can relay numerous messages about current freeway construction and maintenance work zone conditions, and because they have the ability to command attention, they are very effective when used properly. However, when they are not used properly these signs begin to lose their ability to command attention and are ignored by motorists. In order for the signs to be effective, everything possible must be done to assure that messages displayed on these devices are accurate and current at all times. To improve the operations of these devices, one must determine where the need for improvement is most prevalent. This study used a survey to examine the practices of numerous entities across the United States and Canada in an attempt to identify impediments to the effective and efficient use of these portable variable message signs used in freeway construction and maintenance work zones. Once information about operating practices were gathered from the participating entities, the various operating procedures used were compared to procedures recommended by researchers who determined the most beneficial methods of operating these devices. Discrepancies between operating procedures and recommended procedures were noted, along with comments by the entities as to the effectiveness with which the signs performed specific duties. Through this process impediments were associated with certain practices. Recommendations for improving PVMS operations through dealing with impediments were made in many different levels of sign operation. Recommendations in this report deal with personnel issues as well as equipment and technologies used. Certain guidelines and standards are suggested as reference materials to be used in signing operations and in personnel training. Specific guidelines are recommended regarding message length and other message display issues. Techniques for signing and personnel procedures are also addressed.