What is the meaning of a white rectangular sign?

A white rectangular sign provides regulatory information, which typically includes critical rules that drivers are required to follow. This can encompass various types of directives such as speed limits, no parking zones, or other prohibitions that help maintain order and safety on the road. The use of white rectangles for these purposes helps to ensure that such important regulations are easily visible and clearly understood by drivers.

In contrast, other options represent different types of road signage: warning signs serve to alert drivers to potential hazards; service signs provide information about services available in the area; and directional signs assist with navigation. However, these do not align with the specific purpose of white rectangular signs, which are dedicated to conveying regulatory information that drivers must adhere to while operating a vehicle.