Tinted lenses on green LED traffic signals

[Pink Jazz]

One thing I have noticed around here is that with most LED traffic signals, the red and yellow indications usually have tinted lenses while the green indications usually do not, except on some (not all) of the newer "incandescent look" signals. 

I wonder what is the reason?  Is this common practice by many cities?  Could the reason be related to color blindness, sun phantoming, or a combination of both?

[busman_49]

Sunphantom most likely.  It's okay to mistakenly think the red and yellow are lit, but not for the green

[andrewkbrown]

I've noticed and wondered the same thing, as Washington DC's traffic lights are the same way. Maybe something to do with green LEDs not shining brightly enough through a green tinted lens?

https://maps.google.com/maps?q=Washington,+DC&hl=en&ll=38.896124,-77.011364&spn=0.01483,0.033023&sll=37.6,-95.665&sspn=60.181414,135.263672&oq=was&t=h&hnear=Washington,+District+of+Columbia&z=16&layer=c&cbll=38.896124,-77.011364&panoid=k-zXAp6jz6DuCl9IKBXkNw&cbp=12,146.2,,1,-2.05

[busman_49]

I've noticed and wondered the same thing, as Washington DC's traffic lights are the same way. Maybe something to do with green LEDs not shining brightly enough through a green tinted lens?

Not really the case.  Ohio has green tinted LEDs all over the place and they work just fine.  It has to do with sunphantom and not wanting drivers to think the green light is on when it really isn't.

[Pink Jazz]

Not really the case.  Ohio has green tinted LEDs all over the place and they work just fine.  It has to do with sunphantom and not wanting drivers to think the green light is on when it really isn't.

Some (not all) of the newer "incandescent look" signals in Gilbert and Mesa have green tinted lenses.  I wonder if these are less prone to sun phantoming than the older style LED signals.

[Revive 755]

Link to brief MNDOT study on green lenses that is relevant to this thread.