Delineation effects in overtaking lane design

The research explored the relative merits of several forms of overtaking lane delineation and signage treatments in the safe and controlled environment of a simulated driving task. The experiment compared the effects of three lane marking and signage treatments across six different overtaking sites. At sites where forward visibility was restricted due to the topography or road geometry, there were pronounced differences in drivers’ lane position, speed, and the number of vehicles overtaken. The presence of a continuity line used in the diverge portion of two of the treatments was successful in moving more drivers to the left (slow) lane. A continuity line at the end of the merge portion of one treatment delayed drivers’ merging and was associated with shorter headway distances.