Final answer:
A pennant-shaped sign on the road typically signals a no passing zone, alerting drivers that it is unsafe to overtake other vehicles in that area.
Step-by-step explanation:
A pennant-shaped sign on the road usually indicates a no passing zone. It is typically found on the left side of the road in countries where driving is on the right. The sign is intended as a warning to drivers that it is not safe to pass another vehicle on the road ahead, often due to reduced visibility or upcoming changes in the road such as curves or hills.