Rectangular, black letters on a white background signs are used as:

Rectangular signs with black letters on a white background are universally recognized as regulatory signs. These signs serve the purpose of informing drivers about specific laws and regulations that must be followed. For instance, they may indicate speed limits, parking restrictions, or other important regulations that govern road use. Their clear and straightforward design is intended to ensure that information is easily readable from a distance, promoting compliance with traffic laws. This is essential for maintaining order and safety on the road.

Other types of signs have different designs and purposes: warning signs typically use yellow and black colors to alert drivers to potential hazards; informational signs provide useful information regarding services or points of interest, often featuring different colors and symbols; and directional signs help guide motorists to their destinations with arrows and location names. Each type has a specific intention behind its design and color scheme, ensuring that drivers can quickly and effectively interpret the information being conveyed.