Civil Engineering Reference
In-Depth Information
power plants, and machinery today generate accidents that did not occur 50 years ago.
Yet society matures with time, and there is a general trend downwards for all types of
accidents—for fatalities as well as injuries. For traffic accidents, Smeed (1952, 1968, and
1974) and Smith (1999) proved an interesting trend, which is referred to as Smeed's Law
(see Figure 18.1).
In the lower right corner, the number of vehicles per capita is very high. This part of
the figure refers to countries such as Australia, France, Sweden, and the U.S. They also
have a very low fatality rate. In the upper left corner are developing countries, including
many African and Asian countries. Their fatality rate is 20 times as high as for developed
countries. A very high correlation coefficient was obtained for the data in Figure 18.1
with R
2
=0.97.
Smeed explained the results in following way: with time and with greater
motorization, procedures and traffic measures in countries improve. There are
improvements in legislation, roads, and vehicle inspections. Developing countries lack
much of the infrastructure to support traffic. The legislation, driver training,
FIGURE 18.1
Numbers of fatalities D
per 1000 motor vehicles (vertical axis)
plotted as a function N- of the number
of motor vehicles per capita (horizontal
axis). Each number corresponds to a
country.
and traffic rules and laws have not been fully developed. But over time developing
countries will develop; driver training and traffic legislation will improve. Also, with an
increasing number of vehicles the infrastructure improves with better roads, regulations,
and training.
