If there is an obstruction in the road ahead, it is legal to cross to the left of a solid double lane marker in a no-passing zone if the roadway ahead is clear.

A solid double lane marker indicates a no-passing zone, meaning that drivers should not cross this line to overtake other vehicles. The purpose of this rule is to ensure safety and maintain the flow of traffic, particularly in areas where visibility is limited or where there may be potential hazards.

In this scenario, if there is an obstruction in the road ahead, the rules still apply. The legality of crossing a solid double lane marker generally does not change simply because the road may be temporarily obstructed. The primary concern is safety and the potential for unexpected circumstances, which could arise when making such a maneuver.

However, while certain exceptional conditions may allow for temporary crossing of lane markers in specific emergency situations, it is essential to prioritize safety and obey traffic laws designed to protect everyone on the road. Thus, the answer indicates a misunderstanding of the legal framework in place regarding lane markings and passing zones.