Final answer:
Two sets of solid double yellow lines spaced 2 feet or more apart signify a No passing zone, indicating that passing is not allowed for safety reasons.
Step-by-step explanation:
Two sets of solid double yellow lines spaced 2 feet or more apart are considered a No passing zone. This road marking indicates that passing other vehicles or changing lanes is not allowed in either direction. Such markings are there to ensure pedestrian safety and to regulate traffic flow, especially in areas where visibility is limited or it's dangerous to overtake. For example, in the vicinity of a school campus where students frequently need to cross the road, delineating no passing zones helps in reducing the likelihood of accidents. A traffic signal in such areas further enhances safety by allowing pedestrians to cross at designated times and by compelling vehicles to slow down, respecting the posted speed limit.