True or False: White rectangular signs are used to indicate rules that drivers must obey.

White rectangular signs are indeed used to indicate rules that drivers must obey, making the statement true. These signs serve as regulatory signs, providing important information such as speed limits, no parking zones, and other essential traffic regulations that drivers are legally required to follow.

In the context of traffic sign categories, rectangular signs typically convey rules and regulations that help maintain order and safety on the road. This is crucial for drivers to understand as it directly influences their driving behavior and compliance with traffic laws. Compliance with these signs is mandatory and helps to ensure the safety of all road users.

The other options present different scenarios that do not accurately reflect the usage of white rectangular signs. For instance, stating that such signs are only used in urban areas or only at intersections is misleading, as these signs are present in a variety of locations, including rural areas and highways, and cover numerous regulations beyond just specific regions or points of intersection.