Final answer:
Placarded vehicles cannot be parked within 25 feet of an open fire to ensure fire safety.
Step-by-step explanation:
Placarded vehicles cannot be parked within 25 feet of an open fire. This regulation is important for fire safety reasons, as placarded vehicles carry hazardous materials that could pose a risk if they were to catch fire. By keeping these vehicles a safe distance away from open flames, the risk of a potential fire spreading or causing an explosion is reduced.