This is a letter height visibility chart pinned on our Pinterest page. It is a reference detailing recommended letter height for signs based on distance from a sign. It lists the absolute maximum distance you would be able to read the text as well as the recommended max distance before the text loses impact.
This is a similar graphic. It compares speed someone is traveling to letter height, to provide text height recommendations.
As you can see, there are many options to consider when choosing the right sign for your next project. Sign Authority can help.