What shape is the pennant sign, which indicates no passing?

The pennant sign that indicates no passing is shaped like an isosceles triangle. This distinctive shape is used to alert drivers that overtaking is prohibited in the designated area. The triangular design is significant as it provides a clear visual signal that commands attention and conveys the critical message of safety and caution on the road.

In contrast, other shapes like the diamond shape are typically used for warning signs, circles are utilized for regulatory signs such as prohibitive or mandatory actions, and rectangles often indicate guidance or information. The triangular pennant shape specifically helps drivers quickly recognize the no passing zone, promoting safer driving practices.