Credo si tratti delle linee di mezzeria, che e' in definitiva un altro metodo per indicare il senso di marcia
Presuppongo che sia il sinonimo di Pavement Edge Lines
Pavement edge line markings delineate the left or right edge of the road. Edge line markings may be placed on roadway features such as horizontal curves, narrow bridges, pavement width transitions, and curvilinear alignments. They have unique value as a visual reference for the guidance of drivers during adverse weather and visibility conditions. Pavement edge lines on two-lane roadways shall be a solid white color and edge lines shall not be continued through intersections or be broken for driveway access.
http://www.showmeboone.com/PW/WebPublish/TSM-PavementMarking...