Dave:
Obviously it would be silly to suggest that pouring the light on an intruder was in any way whatsoever unjustified. I never meant that, and I haven't ever heard any lighting professionals say that, either. I also suspect that you only have those lights trigger when someone actually is intruding, and don't have your yard lit up like Times Square 24/7/365. I also agree that lights coming on when someone walks up to your house will tend to deter them from proceeding further.
My point, which I guess I pretty poorly explained, is that cities have tons of crime. If you walk down the streets of any medium- or large-size city, you will find it is lit up like daylight. However plenty of crime still occurs. Light is obviously not a deterrent in this case, because it is the natural environment (unlike the case of home spots which come on automagically, as mine and yours do). Thus, the criminals learn to operate "in the light". Otherwise, if light is all it took to deter crime at night, there would be zero crime at night in big cities. I think we can both agree that is not the case
.
The way that we can help our city leaders to make lighting more effective in inhibiting crime is to urge them to use lighting that, instead of glaring (and thus blinding) people, and creating dark pools between the well lit areas for criminals to hide in, evenly lights the scene on the ground everywhere, so the criminals have no place to hide. This DOES NOT mean fewer lighting fixtures, and in fact might mean more in many cases. However, with power costs increasing all the time, cities should be installing fixtures (of which there are many to choose from) which put 100% of their light on the ground, where it is needed. I think we can agree (or at least I hope so) that a fixture that puts 30-50% of its light above its horizon is a wasteful fixture that is not properly lighting the area it is intended to light. If it's lighting the sky, it's wasting money and the percentage of light above the horizon is doing *absolutely nothing* to deter crime whatsoever.
This is what the IDA is all about, NOT trying to get lights turned off.
Regards,
--Lee