The objective of this study was to investigate the ability of various traffic control measures to delineate horizontal curves so drivers would perceive the curve and slow to an appropriate speed and then be provided guidance through the curve. Pavement delineation (raised pavement markers, transverse stripes, or rumble strips) and shoulder delineation (post delineators and chevron signs) were used. A laboratory test found that a post delineator configuration in which the distance from the post to the pavement edge and the post spacing remained constant while the height of the delineator on the post increased made a curve appear sharper than other delineator configurations. The delineation treatments did not dramatically decrease speeds at the point of curve, but encroachments decreased substantially and the severity of the encroachments was reduced at locations that originally had a high proportion of moderate or severe encroachments. Pavement delineation had more of an affect than shoulder delineation. Also, chevron signs were more effective than post delineators.

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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, the Federal Highway Administration, no the Kentucky Transportation Cabinet. This report does not constitute a standard, specification, or regulation.