This synthesis will be of interest to traffic engineers, planners, and others interested in making sure that motorists' needs for directional information on freeways are being met. Information is provided on policies and procedures used by states in evaluating freeway guide signs and replacing those that are outdated or deteriorated. Many signs on freeways and other controlled-access highways have exceeded their service life and are no longer serving motorists' needs. This report of the Transportation Research Board describes the policies, proceduress, and criteria used by states for freeway sign evaluation and replacement programs.

This report contains the results of a three-phase human factors study which tested driver comprehension of diagrammatic freeway guide signs and their text alternatives. Four different interchange types were tested: left optional exit, left lane drop, freeway to freeway split with optional center lane, and two lane right exits with optional lanes. Three phases of the project tested comprehension by using digitally edited photographs of advance guide signs in freeway scenes. Participants viewed a computer slideshow in which slides were shown for only three seconds to simulate a single driver eye glance at a sign. All signs were mounted overhead in the photographs. Participants were provided a route number and city name as a destination that could be reached either by the through route or the exit route. They indicated which lane or lanes they would choose to reach the given destination. The fourth phase of the study used a fixed-base driving simulator which presented full sign sequences consisting of two advance guides and one exit direction sign. This report also contains an extensive literature review of previous work in the area, a discussion of testing methodology, and suggestions for future research.

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.