Light pollution again

[MarkS]

Flying into Heathrow on Saturday night, the sky was clear and I had a window seat.  I noticed something encouraging.  A lot of the arterial roads (motorways and dual carriageways) had a very "fuzzy" appearance.  I quickly realised the reason was that I couldn't see the individual streetlights - they were full cut-off lights - all I could see was the illuminated patches of road beneath them.  This is quite a positive development - it means that no light was escaping directly upwards from the streetlights on those roads.

If all streetlights can be replaced with these new ones and if the worst offenders, external warehouse and factory lights, can be better controlled then I think there is hope for reducing overall light pollution.

I have also recently noticed that all the streetlamps on the M20 are of the full cut off type - see here:
http://www.britastro.org/dark-skies/goodvbad.htm

Mark

[Tony G]

I noticed this last week myself when it was misty/foggy on the M25. All the new lighting being erected on the new widened sections in Essex and Hertfordshire, had the new cut off type, and the mist could only be seen below, whereas the old type lit up the sky above.
Now due to the prospect of clearer skies, I have to sit in the traffic in the roadworks where these lights are being fitted, and then sit in 4 lanes of traffic instead of the 3 lanes at present.

Tony G