Lines, symbols, and words painted on a roadway help to direct riders and control traffic flow. You must know what the different lines and colors mean and obey them as you would traffic signs or signals. White and yellow lines are used along pavement edges and between lanes to keep vehicles in line. These lines may be solid or broken (long dashes), single or double. A solid white or solid yellow line that turns into a dotted line (short dashes) is a continuation of the line through an intersection or a highway interchange.