I don't think LEDs are going to cut it... Seems to me you'd want IR lights with reflectors, similar to regular headlights, so you'd get vision at a distance like you do with regular headlights. And in the ~50 watt range, too. Does anyone make incandescent IR lights? It'd be sweet if you could convert a set of regular driving lights to IR.
I'm not aware of any IR-based sensors out there, and I would be surprised if these interfered with traffic cameras any more than regular headlights. I'm just guessing though.