Question about meaning of the word "across"

Question

A U-turn is turning your vehicle around in the street to go back the way you came. To make a U-turn, signal and use the far left lane or the center left turn lane. You may make a legal U-turn: Across a double yellow line when it is safe and legal.In a residential district:If there are no vehicles approaching you within 200 feet.Whenever a traffic sign, light, or signal protects you from approaching vehicles.At an intersection on a green light or green arrow, unless a "No Uturn" sign is posted.On a divided highway, only if an opening is provided in the center divider.

When saying across, does it mean on the line / over the line or after a finished line?

Answer 1

In order to perform a U-turn, you naturally have to cross from one side of the road to the other. In the US, a double yellow line down the middle of the road indicates that you cannot pass (overtake) on that road.

The quote you have provided is clarifying the point that although you cannot pass by crossing double yellow lines, you can perform a U-turn by crossing them, if safe and legal to do so.

Answer 2

Graphical Aid

In general, a "double yellow line" is the lane marking that shows up in image A (from a California handbook, so the rules you are studying might be different).

Crossing that line means to go from one side of the line to the other side, in a way that the line of paint is underneath the vehicle at some point. Like in image A. In image B, the car is not crossing the line, because the line ends/is finished before the driver makes the turn.

(Double yellow lines means "Do not cross for any reason!" You aren't supposed to cross any solid yellow line (single or double) for passing purposes, but depending on the state, you may be allowed to pass over the double yellow line to make a left turn (that's what A illustrates in my link) or to make a U-turn, as in your driver's handbook.)