You seem to be on-topic to me, Steve. The articles you linked, while very informative, seem to be a little hard to believe. I mean, it’s difficult to imagine the precision involved in guessing incandescent light fade.
But you know, since these guys do it for a living, then perhaps you have a very good point about the effect on their reaction times. It’s difficult for me to imagine, still.
I don’t have the article handy, nor do I remember if it was talking about traffic lights or taillights, but it did state that because the lights came on faster it can enable a driver to respond quicker and thus stop sooner. This distance was not all the great as I recall, but was definately noticable.
And it’s not just NHRA drivers who watch for things like fade. In high school, a bunch of us used to do it with traffic lights as well. (I still do it with on particular traffic light since it seems to hate me.)
:dubious:
Well, let’s see. I can’t find any information on incandescent lamp turn-on times in a quick search, but I don’t believe 1/100 second is unreasonable. At 60 MPH, or 88 ft/s that’s a distance of .88 ft. or a whole 9.6 inches, assuming the LED turn-on time is zero, which it isn’t. Measureable, yes, but I’d hardly call it a noticeable difference, especially with the variability of reaction time between individuals, and even with the same individual at different times and under different circumstances.
Dunno. I don’t remember the figures I saw, so I won’t dare posit a guess.
In the interrest of fairness, here is a PDF article that appears to back up your position, Tuckerfan. However, I will contend that this study is flawed. For one thing it’s written by Hewlett Packard, one company that manufactures assemblies and components for LED stop lights and automotive lamps, but do not also make similar incandescent fixtures. For another, the study used 0 - 90% brightness as it’s lamp turn-on time criterion, but this ignores the fact that the light is sufficiently bright enough to see long before attaining 90% brightenss. The brightness rise curve is not linear, but follows a sharp curve. Initially, brightness increases more rapidly than it does as the filament begins to heat up, because the resistance is lower when the filament is cold, and rises as it heats up. So, I still think the signal is too buried in the noise to be meaningful.