I think what you are noticing is that the frequency of light emitted from halogen is very wide and generally warmer in color (almost orange), but at the other end of the scale, LED lights are a very narrow range of (blue white) light frequencies whilst being energy efficient makes it harder to see at night because the eyes are not used to this narrow band of light frequencies.
What I dont like about LED's is I can see them flickering in some situations, you dont get that with the warmer halogen bulbs, but even with halogen bulbs, you can see how a car is wired by seeing which brake light comes on first as the electricity moves down the circuit to the next brake light. In other words you can work out what side the wiring loom runs down to the back of the car!
> you can see how a car is wired by seeing which brake light comes on first as the electricity moves down the circuit to the next brake light
Suppose the loom doesn't run from brake to brake, but instead runs all the way back to the front of the car and back, for a 10 meter total run. With electricity traveling in wires at roughly two thirds the speed of light, this is just about 50 nanoseconds.
While sensitivity to slight timing differences can be acute (is there a term for the temporal equivalent of Vernier acuity?), detecting a 50 ns difference is implausible.
Some manufacturers are worse than others, Vauxhalls and Fords I could often see the delay between the two rear lights coming on. When ever I've had passengers in the car, I've asked them if they can tell which brake light is coming on first most dont notice it until I point it out.
Anyway just because you dont believe me doesnt mean I'm wrong!
What I dont like about LED's is I can see them flickering in some situations, you dont get that with the warmer halogen bulbs, but even with halogen bulbs, you can see how a car is wired by seeing which brake light comes on first as the electricity moves down the circuit to the next brake light. In other words you can work out what side the wiring loom runs down to the back of the car!