What do two parallel yellow lines indicate?

Two parallel yellow lines indicate a no passing zone. This means that drivers are prohibited from crossing these lines to overtake or pass other vehicles. The presence of double yellow lines serves as a clear warning that visibility may be limited or that other conditions—such as curves in the road—make passing dangerous.

Unlike a single yellow line, which may allow for passing if it is safe, the double lines emphasize the importance of staying in your lane to maintain safety on the road. It's crucial for drivers to adhere to this marking to prevent collisions or accidents, ensuring everyone on the road can navigate safely.