Outdoor Lighting and Crime - Amper

composite Curve E/F for the 21 cities involved is also positive over the illuminance range
applicable. This rules out Curve C and does not support Curve E as a description of the effect
of outdoor light at night on crime as quantified in Figures 9 and 10. A more comprehensive
discussion of some of these points is in Section 5.4.
5.2.4 City crime and upward light energy loss comparisons, Canada
Table 7 presents the earliest readily available crime data set for Canadian cities (1999), along
with light energy loss per unit area arranged in descending order. Crime rate is plotted against
light energy loss per unit area in Figure 11. The data point for Trois Rivières, shown as an
unfilled symbol, is clearly an outlier in this data set. Discarding it gives the regression line an
upward slope that is not reliably different from zero: r 2 = 0.307, t = 1.631, 6 df, ns. Including
Trois Rivières gives a slope of -0.0033, even further from significance: r 2 = 0.027, t = 0.437, 7
df, ns.
TABLE 7. Crime Rate and Upward Light Energy Loss in Canadian Cities
City
Population,
thousands
Crime Rate %
Annual Upward
Light Energy
Loss per Unit
Area, MW.h/km 2
Annual Upward
Light Energy
Loss per
Person, kW.h
Trois Rivières 138 5.56 205 53.6
Calgary 951 7.62 43.9 87.7
Montreal 3 426 7.16 34.4 40.6
Edmonton 938 8.54 32.4 62.8
Toronto 4 683 5.40 31.6 29.3
Quebec 683 4.87 20.8 53.7
Ottawa 999 6.42 20.2 32.6
Chicoutimi 161 5.26 19.1 47.7
Sudbury 166 6.56 14.0 51.0
Light energy loss measurements are from a satellite in 1997 (Isobe and Hamamura 1998).
Population and crime data are for 1999, from Statistics Canada (2001). The 1999 crime
rate values were calculated from percentage changes given for 2000 values. Crime rate is
plotted against the light energy loss data in Figures 11 and 12.
Plotting the crime data against light energy loss per person (Figure 12) gives a positive trend
but again the slope is not reliably different from zero: t = 1.427, 7 df, ns. Trois Rivières is not
an outlier in this figure.
For the satellite observation date of 1997-01-12, Wunderground (2003) provided information
on weather in the cities with the exception of Trois Rivières, Ottawa and Chicoutimi. No
snow depth was given for Quebec and Montreal but snow events were recorded in both places
and temperatures remained well below freezing. The remaining cities had snow depths
ranging from 140 mm to 531 mm. It is possible that differential effects on the terrain
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