Thanks for all the replies, pro and con, ladies. I appreciate them. Just to clarify, the rider was in a safe area when I did yell. He was on the other side of the traffic cones on a fresh new lane (no cars allowed) by then. I did consider where he was before I rolled down my window. Being a cyclist myself, I know how easy it is to be startled by a driver saying anything, and I wouldn't have said a word if I'd passed him on the skinny traffic lane as that would have been way too dangerous.

I have passed lots of non-helmeted cyclists in my time, and have never said anything (other than to my DH or under my breath). I have also seen cyclists riding on the wrong side of the road and have only said something once, when they were coming right towards me. I usually mind my own business. Perhaps I should have this time, but I bet he won't forget his helmet next time!

I've also seen several segments on various news programs where they've staged people being harrassed, robbed, or whatever, and so many people just walk right by and won't get involved. Male bystanders more often just walk by. Women are more likely to get involved and to stand up for the victim. Sometimes getting involved could save someone's life. I am certainly not saying that I saved this guy's life by any means, but as I contemplated saying something to him, thoughts of these types of scenarios ran through my mind. I didn't want to be one of the ones who just "walked by" and let someone get hurt. I hope he pulled over later and put on his helmet.

Thanks about the sticker, Grog, but as a 40-something married woman, I think I'll pass. My DH might not take to me considering the hotness of anyone else on a bike, even if it is said in jest.

Emily