What does it mean when there are jagged lines on both sides of a dashed line?

[MacRonan]

Jagged lines on both sides of a dashed line are longitudinal deceleration markings on highways, which can be divided into transverse deceleration markings and longitudinal deceleration markings. They are white dashed lines set up in toll plaza areas, exit ramps, or other sections where vehicle speed reduction is required. These markings come in forms of single dashed lines, double dashed lines, or triple dashed lines, set perpendicular to the direction of travel. The longitudinal deceleration markings for traffic lanes consist of a series of diamond-shaped dashed lines parallel to the lane dividing lines, typically installed at bridge approaches, turns, and other locations. Their primary function is to create a visual narrowing of the lane, inducing a sense of pressure to prompt drivers to automatically reduce speed at curves, slopes, and other areas where deceleration is needed. Whether lane changes are permitted under these deceleration markings depends on the state of the adjacent markings: lane changes are not allowed if the adjacent line is solid, but are permitted if it is dashed.