That would be a question for CALTRANS. If you have FastTRAK - which you should - and you go over one of the Bay Area's many bridges regularly - which I do - the toll sign that flashes the amount of money you've paid instead flashes the message, "Valid, Etc.". I came to take this as my personal electronic affirmation each day when I crossed the bridge. Not a well thought out or thorough affirmation, though. More like a fortune cookie. "Jacqueline, you're valid and well...etc." I guess there wasn't enough room on the toll sign to add "blah, blah, blah". Me and the other 270,000 commuters who travel the bridge each day, we're just valid, etc..