Women's Safety in Traffic

Q: When riding to work I often see women cycling with their headphones in, filtering down the side of lorries and generally being dangerous. It's common knowledge that proportionally female cyclists are killed more often than male cyclists. So... How do I tell them to stop without sounding like a patronising prick?

Been thinking about this too. What about a small card you can hand out to them? Sometimes there's not time even for a brief chat if the lights are about to turn green. And on a card there could be illustration and what not

Also that can be read and taken in without some know-it-all prick telling you you're a shit cyclist at a red light