Abstract
This paper reviews literature related to travel on rural roads at night and to the problem of negotiating curves. That a problem exists is inferred from relevant accident data. The problem is identified With a lack of usable visual information which delineates the path of the road ahead and the nature of any change in that path. There is some evidence that the perception of road curvature, which is necessary to select an adequate speed for negotiation, in the daytime can be made difficult by certain subtle factors hadden in the visual perspective of the curve. The use of driver vehicle performance measures as criteria of the effectiveness of delineation treatments, and various studies on comparing delineation treatments are examined.