That's interesting. I've never heard of a local law like that. I would think common sense would dictate that a constant white light would at least be legal in that situation, otherwise the law is essentially making it impossible for a cyclist to be able to illuminate their path on a dark night. (In this case, I'm talking about laws that were written a long time ago, where cyclists rode more slowly than now, and often on less heavily travelled roads, so seeing the road was more important than being seen by cars, which is a higher concern in most places nowadays.)

I live in San Francisco, so there are tons of people who commute to work via bicycle. I used to ride a lot but in my personal risk-benefit calculation, I think the risk is too great to commute by bike from my house to work everyday. Anyway, to be seen by others, I think a flashing white light makes the most sense. Most motorists equate white light with something headed your way, and red with something moving away from you. Amber? That's iffy, and requires the driver to concentrate harder to figure out what is going on.

However, as has been mentioned earlier, too many cyclists use a combination of a very bright LED light and aim them too high. Dazzling drivers does not enhance cyclist safety and just annoys everyone else. That said, it's almost unbelievable how bright some bike lights are now. I'll be walking down the street in the dark and I sometimes see a big wall of light approaching from behind. Is it a silent hybrid car coming up (a common occurence here)? No, it's a cyclist! Amazing.

But really, I think raising the awareness of motorists is the biggest contributor to improving safety. And that goes for making things safer for motorcyclists, too. Illumination and reflectors only help so much, but if a car makes a bonehead move when a bicycle is right there, the only way the motorist knows you're there is when the cyclist comes flying onto the hood of the car.