I think I am right too.
Here is a link
http://deepblue.lib.umich.edu/bitstr...9402600202.pdf
PHD types out of michigan. They actually claim a quarter second to reach 90% light output. Detail their methods etc etc.
Anyway don't take my word, or theirs for it look around! Some cars have mixed technology tail lights 3rd brake lite will be LED and corner lights incandescent.
In these cars you will notice a delay between when the LED lamp comes on and when the incandescent lights come on.
My point was only that while it seems pretty clear that LED lamps won't pay for themselves in saved gas, there is a chance they will pay for themselves in avoided body work and chiropractic