"Metro officials who have long striven to keep the transit system uncluttered say financial pressures have forced a new philosophy: They want to turn rail cars and buses into rolling billboards, run animated commercials in dark subway tunnels, hang video monitors inside trains to broadcast commercials and welcome ATMs, florists and shoe cobblers at stations in exchange for a cut of the action.

[...]

"Transit officials also plan to drape advertising from the sides of parking garages, hang commercial banners from banisters inside the busiest stations, hoist advertising signs on light poles in station parking lots and sell ad space on bus shelters. "We want to leave no stone unturned," said Leona Agouridis, Metro's assistant general manager for communications.

Advertising is really losing its effectiveness, isn't it? We live in a virtual cesspool of advertising. There are ads on the ice freezers at convenience stores, on police cars, and above urinals in bathrooms.

What do you think about the whole billboard/free speech issue? Can billboards be constitutionally banned as they are in some states? Or only regulated? Or regulated at all? I have mixed feelings personally, and I wonder what the legal issues are.

There is an incredible amount of law on billboards, and I'm not very familiar with it. I think courts have generally found a significant state interest in keeping cities/highways free of clutter, and that has allowed some restrictions on billboards.