This synthesis will be of interest to traffic engineers, maintenance managers, sign shop supervisors, and others interested in the maintenance of street and highway signs. Detailed information is presented on the current practices of state and local governments in managing the maintenance of street and highway signs within their jurisdictions. The maintenance of street and highway signs is viewed as a means for improving the effectiveness of a signing system. This report of the Transportation Research Board describes the maintenance practices of several state and local highway agencies along with the rationale for those practices. It covers inspection, refurbishing, and replacement practices, along with information on equipment and personnel requirements.

A replacement to the publication entitled 'Highway design and operational practices related to highway safety', also known as 'The Yellow Book', and most recently published in 1974.

Modern highway engineering reflects an integrated view of a road system's entire lifecycle, including any potential environmental impacts, and seeks to develop a sustainable infrastructure through careful planning and active management. This trend is not limited to developed nations, but is recognized across the globe. Edited by renowned authority

TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 431: Practices to Manage Traffic Sign Retroreflectivity includes examples of practices that illustrate how different types of transportation agencies might meet federal retroreflectivity requirements for traffic signs.

The report is designed to help the commercial transportation safety community and the Federal Motor Carrier Safety Administration in addressing issues involving the proliferation and availability of psychoactive chemical substances.