A reflector that gradually fades into view? That's part of the problem with reflective stuff at longer ranges... it gradually ramps up in intensity. It has to reach a threshold to be conciously noticed, and then has to be assessed until it's at least recognized as an obstacle, if not a cyclist. By contrast, a flashing taillight is associated with cyclists and pedestrians in the U.S.; it has a sharp ON/OFF contrast to catch the viewer's eye rather than gradually fading into view; and its apparent intensity doesn't drop off nearly as badly with distance, rain, snow or fog.
Also, if you think a 10-second window is a good buffer for the driver of a loaded semi truck, I don't see that IRL. Out on the divided highway, I ride at the right half of a wide shoulder like this one, and the semi drivers will still divert to the left lane at long range (1/4 mile or more), if they have an opening. Given that their priority is obviously to give me tons of room without having to make last-second lane changes, I'm sure they appreciate that I do NOT start showing up at close range, particularly when traction's not so great (snow, ice, rain).
And yes, 10 seconds is close range. When I drive a car at highway speeds, my typical following distance on cars going
my speed is around 8-10 seconds, let alone something I'm overtaking at a 45mph speed differential. If I'm heading for an exit ramp at 50-60mph, I want to see cyclists from as far as practical so I can allow for the possibility they're not exiting where I am, and even a modest blinkie like a SuperFlash will totally trump reflectors for that purpose in darkness. In daylight, a hi-vis outerwear does help a lot, although anecdotal reports from a co-worker shows that my best-of-breed taillights are still the first thing he noticed at 1/2 mile in daylight.
