What does a double yellow line on the road signify?

A double yellow line on the road signifies that no crossing the center line for passing is allowed. This marking indicates a no-passing zone, meaning that vehicles must stay in their lane and not attempt to overtake vehicles in the opposing lane. It serves as a safety measure to reduce the risk of head-on collisions by alerting drivers that conditions are not safe for passing due to visibility issues, traffic flow, or other hazards. Proper understanding of traffic markings like double yellow lines is essential for maintaining road safety and following the rules of the road.