Double solid white lines on a roadway indicate:

• A. They separate two lanes of traffic traveling in the same direction and crossing is not allowed
• B. They mark the edge of the roadway
• C. They indicate a passing zone
• D. They separate lanes of traffic traveling in opposite directions

Answer: (A)

Double solid white lines mean you must not cross or change lanes. They separate two lanes of traffic moving in the same direction and are placed to discourage lane changes where it would be unsafe. This helps keep vehicles in their lanes on high-speed or congested roads. They aren’t marking the edge of the roadway—that’s a different kind of line—and they aren’t a sign of a passing zone, which is shown by dashed lines. They also don’t separate traffic traveling in opposite directions—that's shown by yellow lines. So the essential idea is to stay in your lane and not cross these lines.