[ScottFromSpokane]

No, a light honk on the horn distracts them and makes it more likely that they will swerve into your path. Trust me.

It's even worse if they don't have a rear-view mirror and they think they have to turn suddenly and see why the hell someone's honking at them.

Just slow slightly, move to the left until you can clear them by at least three feet (at city speeds; more if you're going faster), then drive past them in a nice straight line.

[Max Combined]

"No, a light honk on the horn distracts them and makes it more likely that they will swerve into your path. Trust me."

I don't trust you and I don't agree. I have been a cyclist and I am a driver and my opinion on this matter is every bit as informed as your own.