Which shape is commonly associated with regulatory signs?

Regulatory signs are essential in conveying rules that drivers must follow, and they are most commonly associated with the rectangular shape. This shape is used because it provides a clear and straightforward visual structure that is easily recognizable, which is vital for quick comprehension while driving. Rectangular signs typically convey regulations such as speed limits, lane use, and parking restrictions, allowing drivers to understand their responsibilities on the road.

In contrast, other shapes have specific uses: circular signs are generally used for warning signs related to road conditions or signals; triangular signs typically indicate yield; and pentagonal shapes are often associated with school zones. These distinct shapes help categorize road signs, enhancing the clarity and safety of navigation on highways and streets.