I’m also concerned that lots of folks seem to think the brighter == better. Particularly the fact that some of these lights are beyond the maximum brighteness permissible for a rear car light. These silly bright rear lights? on flashing mode? Might as well go shine a laser in the driver’s eye and hope he doesn’t hit you.
I think it depends on circumstances. If I’m riding over the Snake Pass at midnight, I’d rather have a very bright light that someone might see at a distance before they scream up to me at 80mph. If I’m riding in town then I wouldn’t use a really bright light. Anyone aware of any instances of bikes being struck by cars after being dazzled by their rear lights?
In reality, what seems to happen is that the car driver does a ‘wtf is that’, slows down and passes with lots of space to spare. No-one’s ever come close to hitting me. With a conventional rear light, people seem happy to skim past you with a foot to spare – I know which scenario I prefer.
I’m not saying very bright rear lights are a universally good thing, but in some situations – fog is another one – they have their uses. You just need to use a modicum of common sense.
And personally, when driving, I’d rather be able to spot a cyclist well in advance and put up with a little extra glare. Compared to oncoming 4×4 headlights, it’s nothing.