Outdoor Lighting and Crime - Amper

Los Angeles, San Diego’s crime rate could be expected to tend towards that of Los Angeles,
hardly the result intended by the ‘more and brighter’ lighting proponents in San Diego. If the
relighting decision is allowed to stand, collection of serial photometric and crime data well
before and after the relighting should be considered, bearing in mind the problems of
inadequately planned lighting and crime experiments described in Part 1.
Although the study of relatively isolated large-scale opportunities such as the San Diego
relighting may lead to progress in knowledge of lighting and crime, any such advance may
take several more years for sufficient time-series data to be collected. This presumes that
adequate before data are available. As the plan is to replace the low-pressure lights over a
five-year period, the absence of an abrupt change could reduce the sensitivity of the
experiment and make generalisation of the results more difficult. Meanwhile, existing largerscale
evidence relevant to the hypothesis has been identified, and is now presented.
5.2 CRIME AND MEASURES OF CITY LIGHT
5.2.1 Satellite measures of upward light energy losses at night
Satellite measurements of artificial light radiated upward at night from populated areas of
Earth are mentioned in Section 2.1.2 above. After the collapse of the Soviet Union in 1993,
the US Air Force allowed the Operational Linescan System (OLS) of the US Defense
Meteorological Satellite Program (DMSP) to be used on suitable occasions for non-military
scientific observations. Although the nighttime part of the system was designed to detect
clouds illuminated by moonlight, it was found that its sensitivity could be reduced sufficiently
by ground control to allow mostly unsaturated detection of city lights on nights close to New
Moon (eg Elvidge, Baugh, Kihn, Kroehl and Davis 1997; Cinzano, Falchi and Elvidge 2001).
The resolution achievable at the ground is dependent on the viewing geometry from orbit. In
the usual configuration, the projected (binned) pixel size is typically in the order of 2.8 km
square, small enough to give useful indications of the energy emitted by aggregated artificial
light associated with terrestrial human activity at various places. The threshold sensitivity
corresponds to a population density of only about 8 persons per square kilometre (Nakayama
and Elvidge 1999). The availability of data about the upward light emissions of cities and
towns provides an opportunity to test the new hypothesis in the cases where crime data are
also available. Before such tests are described, however, it is important to understand the
limitations of the satellite data.
Isobe and Hamamura (1998) and Isobe (2000) listed upward light energy loss data for 153
cities from 52 different countries. They did not state whether these data were for:
• the DMSP OLS sensor response weighted by the luminosity function or similar to give
the CIE luminosity response,
• the astronomers’ V (visible) band response, or, as appears more likely,
• left unweighted as a measure of radiant energy detected by the sensor, a multiplier
phototube.
The sensor response extends from 0.47 µm to 0.95 µm (Chor-pang Lo 2002), which is not the
0.38 µm to 0.77 µm range of visible light. The sensor response is described as VNIR (visible
and near infrared) by Elvidge et al. (1997). To add to the uncertainty, the data given by Isobe
and Hamamura for cities in Turkey and elsewhere are repeated in a different paper (Aslan and
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