Reference markers were installed on sections of interstates and freeways in Tennessee in 1999 and 2000. An evaluation was conducted to determine if the use of reference markers at spacings of 0.2-mile intervals could improve the effectiveness of emergency response and incident management processes. The evaluation included an.general observational survey, meetings with emergency response personnel, and an opinion survey of the application, placement, color, and overall benefits of the reference markers. The condition of the markers was found to be very good and there appeared to be only minor problems within the relatively short period of time since installation.

Interview and surveys of participants in the emergency response process and others involved in traffic management systems indicate nearly unanimous endorsement of the reference markers. Dispatch personnel indicate that drivers are using the markers for identification of locations where incidents occur, with the resultant effect of a more efficient process for responding to incidents and crashes.

Results indicate highway agency and emergency response personnel generally feel that spacing of the reference markers at 0.2-mile intervals was satisfactory. Responses also indicated increased benefit related to the distinguishable color of blue for the reference markers, specifically related to the consistency with motorists service signs. The increased size of the signs over that used for standard milepost signs did not appear to be an issue with any of those offering opinions and the 18 by 48-inch size is recommended for future use.

Report Date


Report Number


Digital Object Identifier



The contents of this report reflect the views of the authors, who are responsible for the facts and accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the University of Kentucky or the Tennessee Department of Transportation. This report does not constitute a standard, specification, or regulation. The inclusion of manufacturer names and trade names is for identification purposes, and is not considered an endorsement.