Question: Raised line markers on the roadway and shoulder are used to define?
Disambiguated questions and answers: question: Raised line markers on the roadway and shoulder are, parallel to drive directed are used to define?
Raised line markers on the roadway and shoulder are, perpendicular to drive directed are used to define?
answer: median strip, edge lines, and dangerous sections of the road.
deviation from the lane
settled mainline toll plaza, ramp entrances, mountainous areas, continuous sharp turns, downhill sections and the end of the highway, gates and entrances of enterprises, institutions, and school
Natural Questions answer: for increased visibility (from the Wikipedia article "Raised pavement marker")