Question: What is the purpose of solid white lines, separating traffic moving in the same direction? Example the ones leading up to the Lowry tunnel in Minneapolis. Does it make it illegal to change lanes?

Answer: Pavement markings direct and regulate traffic. While there are several different types, we will focus on white lines.

White lines separate lanes of traffic traveling in the same direction. A line composed of white dashes indicates that drivers can change lanes in areas where this type of marking is present. 

A line of shorter and thicker white dashes indicates that the lane will end. 

A solid white line indicates that lane changes are discouraged in areas where this type of marking is present. Solid white lines also mark crosswalks, stop lines at intersections, parking stalls, and the edges of a roadway. 

Double solid white lines indicate that lane changes are prohibited in areas where this type of marking is present. 

A solid white line with a bicycle insignia along the side of the road indicates an area is designated for bicycle traffic only. Bicycles must travel in the same direction as adjacent traffic.

A portion of state statutes were used with permission from the Office of the Revisor of Statutes. If you have any questions concerning traffic related laws or issues in Minnesota, send your questions to Trp. Jesse Grabow – Minnesota State Patrol at 1000 Highway 10 West, Detroit Lakes, MN 56501-2205.  (You can follow him on Twitter @MSPPIO_NW or reach him at,