“Anthropological Invariants in Travel Behavior”, 1994-09 (; similar):
Personal travel appears to be much more under the control of basic instincts than of economic drives. This may be the reason for the systematic mismatch between the results of cost benefit analysis and the actual behavior of travelers. In this paper we put together a list of the basic instincts that drive and contain travelers’ behavior, showing how they mesh with technological progress and economic constraints.
…the empirical conclusion reached by Zahavi is that all over the world the mean exposure time for man is around one hour per day.
…When introducing mechanical transportation with speeds higher than 5 km/hr, the physical size of the city can grow in proportion, as the historical analysis applied to the city of Berlin clearly shows (Figure 2). The commuting fields, based on cars, of a dozen American cities are reported in Figure 3. On the same chart and to the same scale, the Greek villages of Figure 1 are shown in schematic form. Cars make all the difference. As they have a speed of 6 or 7× greater than a pedestrian, they expand daily connected space 6 or 7× in linear terms, or about 50× in area. Ancient cities typically had a maximum population of about 1 million people. Today the population may tend to reach 50 million people in conurbations like Mexico City (Figure 4), with a population density equal to that of Hadrian’s Rome. If the Japanese complete a Shinkansen Maglev (a magnetically levitated train) connecting Tokyo to Osaka in less than one hour with a large transportation capacity, then we may witness a city of 100 million people. If we expand the reasoning, we can muse about a city of 1 billion people, which would require an efficient transportation system with a mean speed of only 150 km/hr.
…There is another fundamental observation made by Zahavi that links instincts and money. Because of its generality it could be dubbed as a money instinct. People spend about 13% of their disposable income on traveling. The percentage is the same in Germany or Canada, now or in 1930. Within this budget, time and money are allocated between the various modes of transport available to the traveller in such a way as to maximize mean speed. The very poor man walks and makes 5 km/day, the very rich man flies and makes 500 km/day. The rest sit in between. People owning a car use it for about one hour a day (Figure 12) and travel about 50 km/day (Figure 13). People who do not have a car spend less than 13% of their disposable income, however, presumably because public services are underrated and consequently there is no possibility of spending that share of income traveling one hour per day (Figure 14). Contrary to the risk of all this “exposure”, the number of people killed by road traffic seems to be invariant to the number of vehicles (Figure 15).
Technology introduces faster and faster means of transportation, which also are more expensive in terms of time of use. These new technologies are introduced roughly every 55 years in tune with the Kondratiev cycle. Their complete adoption takes about 100 years (Figure 16). We are now in the second Kondratiev for cars and most mobility comes from them. It was about 10 km/day earlier, and is now about 40 km/day. Airplanes are making inroads into this situation and they promise to bring the next leap forward in mobility, presumably with the help of Maglev trains. Hypersonic airplanes promise to glue the world into a single territory: the famous global village.