Load up with the brightest lights and geekiest reflective equipment you can find. Then invite them to drive a road that you're riding on at night; once they see how garishly visible you are, it might ease their minds.
Or it might not...in which case, my advice is to ride anyway. I don't understand your remark that your family "won't have it." It's not their decision. They don't need your permission to drive a car, and you don't need theirs to ride a bike.
I don't want to sound cold; it's never easy to see your loved ones unhappy about something, and by all means you should do everything you can to help them understand that your commute is not dangerous.
But trying to keep them happy by letting them make your decisions for you is not healthy; they will learn that (however well-intentioned) emotional blackmail "works", and will keep using the technique. And you will end up resenting them for it. Better to let them know that, while you love them and their concerns matter to you, they don't get to dictate your behavior, nor will you try to dictate theirs.
Last edited by divergence; 08-21-07 at 11:48 AM.