Which of the following colors means "after this point, obey the law"?

The color that signifies "after this point, obey the law" is white. In traffic signage, white is the standard color used for regulatory signs. These signs provide important instructions that drivers must follow, including speed limits, parking regulations, and other rules that ensure safety and order on the roads. The use of white for regulatory signage helps to clearly communicate legal requirements to drivers, emphasizing the necessity to adhere to the specified rules.

The other colors serve different purposes: pink typically denotes incident management or temporary traffic conditions, blue is often used for informational signs related to services, and green primarily indicates directional guidance or distances to destinations. Understanding these color codes is crucial for safe and lawful driving.