Bargman LED conversion

One thing about LEDs: when they turn on (like a blinking turn signal does) the slope from nothing to full brightness is very steep, much steeper than an incandescent bulb. The human eye isn't used to this, most light sources in nature are pretty slowly varying. So when hit by the very fast time constant LED slope, you eye can perceive that unnaturally fast slope as a flash, settling to a lower brightness level than the initial impression. You see this in LED street signals as well. It's probably good for stop lamps and turn signals because it attracts attention, even in the peripheral vision.

There have been some studies done on the perception of brightness between incandescent and LED lights for aircraft. Even at the same luminosity measured by objective instruments, colored LEDs were perceived brighter, due apparently to being more saturated color.