Final answer:
Service signs feature white lettering on a blue background, symbolizing informational signs that assist drivers in locating services and facilities like hospitals and rest areas.
Step-by-step explanation:
Service signs are white on a blue background and provide directions to facilities such as rest areas and hospitals. When interpreting road signage, it is crucial to understand color codes as these are part of a universal system designed to provide clear and quick recognition. The color blue in signage is commonly associated with informational signs that guide drivers to services and facilities. These signs are prevalent along highways and roads, offering valuable direction towards necessities like fuel stops, medical care, and rest areas.