Something I have always wondered about is why billboards are not digital. I mean, it seems pretty archaic to have a bunch of guys go around the city to change the vinyl advertisements all the time. Not only that, but if the billboards were digital, they could be animated and time sensitive!
According to the Chicago Tribune (via AdJab), digital billboards are on the rise:
Digital billboards, which resemble ballpark jumbo video displays but scroll through several static ads each minute, are helping to draw advertisers back to the outdoor medium, as one of the world’s oldest forms of marketing is undergoing a renaissance.
The Tribune article points out that the initial investment for the digital billboards can be quite expensive, but so can the resulting revenue.
In the AdJab post, author Chris Thilk points out that “attracting the eyeballs of someone cruising at 65 miles an hour to a flashing and moving sign” is probably not such a good idea. I don’t know if it would really be that big a problem though. There’s a number of big TV screens around Edmonton, and I don’t recall hearing about them causing any accidents. Besides, lots of cities already have “moving” billboards – those ones that alternate between three different ads.
I say, bring on the digital billboards!
Read: Chicago Tribune
MasterMaq's Blog 
Another reason is the media buy with digital billboards is more expensive than regular billboards. Also, sometimes the screens don’t work or have burnt out lights, so advertisers pay for media and don’t exactly get the most use out of it.
Using LEDs though? I can’t imagine it’s much worse than the traditional vinyl billboard. How many times have you seen it ripped or otherwise damaged? Lots of times probably!