It is over 12 years since I got run down from behind using a flashing rear light. The driver didn't see me; he might have been going too fast (well over 50km/h) but subsequently I paid a bit of attention and there is nothing like a flashing rear light for disappearing into the clutter of car rear and brake lights. If you don't want to be seen amongst a load of cars at going home time use a flashing rear light!
Yeah, but the sane options aren't "flashing" or "static". They're "flashing + static" or "static".
So, assuming you've got a static light, is adding a flashing one beneficial? I reckon the potential advantages are:
1) A flashing light gets people's attention, so they look in the direction of your static light and might judge your position and speed.
2) A flashing light denotes a pedal cycle.
The second I reckon is only really important if you have a pair of static rear lights some horizontal distance apart, which might reasonably be misinterpreted as a more distant motor vehicle. Probably only relevant to trikes, trailers and cargo cycles. But you could argue that it helps a two-wheeler stand out in city clutter.
AUIU the psychology behind the attention-getting principle is a sound one (parallels with safety beacons in aviation), but the question is whether this translates to a safety benefit - or indeed the opposite - on the road.
There's also a practical engineering benefit that a flashing light uses less average power, which means it can be brighter than a static light with the same energy source and thermal limitations. Potentially useful in daylight, but decreasingly so as technology improves.
And there's the pragmatic view that in the unlikely event of some idiot motorist driving into you after failing to look properly, being able to say that you were lit up like a Christmas tree might count in your favour.
