What an absolutely horrible idea. Aren't the streets unsafe enough without people creating more ways to distract drivers? LA should put the kibosh on this now.

wonder how long it will be before they get hacked, and then display whatever the hacker wants it to.

Back in the 90s there was a billboard up in Chicago that had a picture of Dennis Rodman on it. Every couple of weeks they'd change the color of his hair (much like he did in reality). This caused a major backup of traffic as people just had to slow down and look. How do you think drivers will react to this? Bad Idea L.A.

Actually, I've already figured out the mechanics of Hacking these things. It's deplorably simple. They use a dish, much like Direct TV, and anyone who's had one knows it takes almost nothing to disconnect them. A big rock gets it off the programming track.

The REAL hacker, however, will figure out how to replicate it's programming signals and insert their own. Then, you take a pole and move the dish a bit, stick a transmitter on the end of the pole and send your hacked signal, and the board shows whatever you want it to for as long as it takes them to realize it's off the net.

But even without hacking, imagine this:
"Accident on the 405 caused by plasma Advertising.... right down there =>"