Unless your sign is located at an intersection forcing traffic to stop, your audience will be driving past your sign between 20 and 70mph. You have less than 10 seconds to reach them.
If your content piece runs longer than 10 seconds, you are not driving home the entire message and have wasted that one impression. The more wasted impressions you land on your audience, the more likely they are to erase your sign out of their daily routine when passing by.
Take this limited time and MAKE IT COUNT! Don’t waste your advertising real estate on useless information or “filler” content.
Don’t go overboard with text or crazy, distracting designs. At the end of the day, SIMPLICITY IS KEY.