What Factors Make Advertising Cost Effective?

Have you ever taken a trip and during a portion of an interstate freeway you have observed signs that capture your attention and alert you to upcoming services? Sometimes these services are gas stations, restaurants, hotels or motels, or any other service that seems to benefit from catching your attention while driving.

What is it that is effective about that advertising? Is it the pictures? Is it the words? Is it the location? What about the strategy? Can you call it strategy when th