PREDICTIONS – 10 Years Later - Santa Fe Institute

6. A HARD FACT OF LIFE
We can look at this substitution process in detail by focusing on the
early automobile period 1900-1930. We consider again the relative
amounts only, that is, the percentage of cars and horses of the total
number of transport “units” (horses plus cars.) Before 1900, horses
filled 100 percent of the personal transport niche. As the percentage of
cars grew, the share of horses declined, since the sum had to equal 100
percent. The data in Figure 6.1 show only nonfarming horses and
mules.
These trajectories are seen to follow complementary S-curves. In
1915 there are an equal number of horses and cars on the streets, and by
1925 the substitution is more than 90 percent completed. It is interesting
to notice that the fitted S-curve points at somewhat lower ceiling than
100 percent for cars after 1930. This may be related to the fact that a
certain number of horses were not replaced by cars. They are probably
the horses found today in leisure riding and horse racing.
To take another example, more recently steam locomotives were replaced
by diesel or electric ones in most parts of the world. The old
“species” declined in a way reminiscent of diphtheria and tuberculosis.
In his book, The Rise and Fall of Infrastructures, Arnulf Grubler shows
that in the 1950s and 1960s the percentages of steam locomotives in the
United States and the U.S.S.R. declined just as the percentage of horses
had done earlier. The raw data outline an S-curve so clearly that there is
no need to fit them with a curve (Appendix C, Figure 6.1).
The data also show that the Russian and American steam engine decline
curves are ten years apart but strictly parallel. This similarity is
deceptive, however, because of another substitution that was taking
place. These two countries not only differ geographically and culturally
but their dependence on railways is fundamentally different. By
1950,midway through the phasing out of steam in the United States,
transportation by railway seemed to have already yielded to road (highway)
transport, with seven times more roadway length than railway
track (see Chapter Seven). In contrast, by 1960, halfway through the
steam era in the U.S.S.R., railways still flourished with tracks totaling
half the length of all paved roads put together.
Examples of obsolescence such as horses and steam locomotives
illustrate the inevitable takeover by newcomers possessing competitive
advantages. There are always two complementary trajectories in one-to-
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