putting x5 into N at traffic lights
 

hello, good or bad for engine to keep it in neutral when stuck at lights? 3.0d auto is the vehicle if that makes a difference, thanks

nope. wastes more gas as idle rpm is slightly higer than in D.
and extra shifting is bad for the trans.

so no point in doing it

What would be the benefit of doing this? It doesn't make much logical sense to drop it into N white at a signal that is only going to take ... 30-60 seconds?

Only benefit is you don't have to hold the brake.

For reasons stated above, not smart to do it on a regular basis.

if you have foot problems and cant hold the break than pull the ebrake

It makes no difference to the internals of the transmission.

The only difference in wear is to the shift linkage.

Putting it in neutral or park also stops you or at least slows you down from taking evasive action in the event of a pending collision, so it is considered a bad practice in some jurisdictions.

I almost always put mine in neutral at a stoplight... Allows me to give my clutch leg a break! ;)

It also takes a load off the throwout bearing; the TO is spinning with the clutch disengaged.

The question was about an automatic transmission.

Agree with you that a manual transmission should be in neutral at a stoplight.

i never do it, and i know some people that put it in N to roll down at a certain speed when the same thing can be achieved while in drive..

in manual, it is the matter of fact - you can even drop it in N while coasting to the red light, stop sign, etc... if you are driving manual, that means that you are more involved with the operation of the vehicle...
in automatic, for all the above reasons, makes no sense... I totally agree with JCL on the evasive maneuvers in case of a pending collision, hostile takeover, possible carjacking... err... well, at least where i come from or go to... lol...