NYC Taxi advertising

I think taxi cabs in NYC should run a special promotion. Picture this, a classy Kenneth Cole ad on top of a cab with a little offer: "Mention this ad and take $0.50 off you fare!" This would get people looking and remembering the Kenneth Cole ads.

In case too many individuals take them up on this offer, maybe they could run an advertisement locally in the city (not on the cabs) that mentions to take a cab with a Kenneth Cole sign on top of it and mention Kenneth Cole to get $0.50 off.