MYTH #5: SECURITY LIGHTING PREVENTS CRIME
Does
outdoor nighttime lighting prevent crime? The answer is nobody knows. In some
cases, lighting seems to deter crime and it makes people feel more secure, but
in reality they may be just as secure without the lighting. In some cases,
lighting probably increases crime because it draws attention to a house or
business that would otherwise escape attention. Most crimes, violent and
otherwise, take place during the day. After all, criminals need light to do
their work, too. A dusk-to dawn light shining all night in a rural area
probably is an inducement for robbery and vandalism. A passerby might not
otherwise notice that the farmhouse is even there.
An
infrared motion-sensor security light which comes on only when someone steps
into the beam makes a lot of sense. It is only on when needed, thereby
conserving energy. Its sudden illumination serves to frighten away the
criminal. These lights are now beginning to replace some of the all-night
dusk-to-dawn 175 watt mercury vapor lights. This makes good sense from the
economical, environmental, and crime prevention points of view. The
motion-sensor security lights can cause light pollution and light trespass if
too high a wattage spotlight is used, or if they are not aimed down toward the
ground. They should also have some shielding. Do street lights, parking lot
lights, and security lights prevent crime? Maybe yes, maybe no. If they are
overly bright with much glare, they actually make it easier for a criminal to
hide in the deep shadows produced by objects in the harsh glary light and
encourage crime rather than discourage it. Well-lit streets with even, uniform
lighting, low glare, and utilizing fully-shielded fixtures probably have lower
vehicle and pedestrian accident rates. How about bright lights in a parking
lot? How many people do you know whose car has been broken into during the day,
or while directly underneath a light at night? One speaker at a recent lighting
symposium recounted how his car was robbed at a local mall. It sat near a store
entrance and was directly under a bright light!
There
are simply no good scientific studies that convincingly show the relationship
between lighting and crime. Our cities are far more brightly lit than ever.
Yet, the crime rate soars. Maybe lights directly lead to crime. Who knows? One
study at a small eastern college showed almost all violent nighttime crimes
took place in well-lit places. This study, while informative, can not be generalized
to other locales because of the somewhat unique nature of the college and the
college town. Crime is a very complex sociological phenomenon controlled by
many factors, and it will vary considerably from place to place.
It
may be that crime is little affected by nighttime lighting for better or worse.
Main arterial streets should be well lit to reduce automobile and pedestrian
accidents. Busy malls should have good lighting to reduce accidents and perhaps
deter crime. After business hours this lighting can be reduced or even turned
off. Security lighting can be at a relatively low level. This saves money, and
not much light is needed to find your way to a door or find your way out to
your car. Not much light is needed to see a suspicious-looking person loitering
around. No matter what the lighting situation, the proper wattage, not
overkill, should be used, and all light should come from full-cutoff, shielded
fixtures. Low pressure sodium lighting is ideal for many of these applications
because of its very low operating cost.