I have an observation that I will share. I notice that the really bright flashing lights have a huge impact on how drivers behave and it isn't always good IMO.
There is a narrow-ish two lane road that has a guard rail on one side and a STEEP slope right at the road edge on the other on my normal after work ride. I find that the driver behavior that I prefer is passing while allowing 3-4' of space. This is usually possible on this road for all but the widest vehicles, even with oncoming traffic. I am even OK with 2' if they aren't speeding.
The people who really bug me are one of two types. The first are the ones who have to go across the double yellow with all 4 wheels and practically ride in the ditch on the other side. To make matters worse they take their time getting back into their own lane and don't seem to care if there is oncoming traffic or a bend that means they can't see ahead. The other are the ones who refuse to pass even when there is plenty of room. Both tend to p1ss off other drivers who are then likely to blame the cyclist and be hostile toward bikes in the future.
OK so now to get to the point... There is a guy that I sometimes see on the same road. He has one of those super bright flashing lights. Traffic backs up behind him because the traffic that just flew by me now refuses to pass him despite the fact that he rides exactly the same lane position.
So yeah the lights work, but I would personally rather not be the source of a big knot of backed up traffic. There I two reasons why I feel this way. First, I just don't see the need to tick off drivers by impeding traffic. Second, once the nervous nelly that won't pass goes by the drivers behind then are more likely to be aggressive after being stuck behind the knot of traffic for so long.
I usually wear a bright jersey and no lights in the day time and a $6 blinkie at night and seem to get the amount of caution I want from the majority of passing drivers.
Different strokes...