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Do mega-cities have special transport problems?
It is clear from the above account that each of the "mega-cities" has distinct transport problems. Transport conditions are far worse in Lima and Rio de Janeiro than in Buenos Aires or Mexico City. And, in so far as the transport characteristics of Lima are much more similar to those of Bogotá than they are to those of Buenos Aires, it is possible to argue that city size is less important than other factors in determining the nature of transport problems. Whatever their size, Latin American cities share certain organizational and management problems.
A particular problem is that all large Latin American cities rely excessively on their roads. Private car ownership is rising in practically every Latin American city and everywhere the bus dominates the public transport system. While justified in terms of the lower short-term costs, the longer-term social cost of road transport is high. Increasing diseconomies have rarely been passed on in the form of higher charges; most of the consequences of worsening traffic conditions have been assumed by the society at large.
In this sense, the problems of the mega-cities are no different from those of most other large Latin American cities. Traffic congestion begins whenever the bus system becomes saturated. This is determined less by the size of the city than by its shape and land-use structure, which, in turn, dictate the frequency and direction of most journeys. As a result, all Latin American cities suffer from severe traffic congestion, air pollution, too many accidents, and lengthening journey times.
In so far as new kinds of solutions are adopted to remedy traffic problems, mega-cities show few differences from other large cities. Although all five mega-cities have metros in operation or in construction, so do many smaller cities (including Caracas, Medellín, Pôrto Alegre, and Santiago). Attempts to reduce congestion by increasing road capacity lead to similar kinds of problems whatever the size of the city. The building of motorways tends to fragment urban space. While Mexico City and São Paulo suffer particularly badly from this process, so does Caracas.
Nevertheless, transport systems in very large cities in Latin America do appear to suffer more seriously from three particular problems. First, the absolute numbers of passengers needing to be transported along key access routes is much higher than in smaller cities. Second, the largest cities tend to suffer from worse levels of traffic congestion. Finally, average journey times tend to be much longer than in smaller cities. Each of these problems tends to become more acute as cities grow in size.
(a) Congestion along key access routes:
All Latin American cities have grown through territorial expansion and through densification along their principal transport corridors. The existing roads have had to carry ever-increasing numbers of vehicles, a problem accentuated by the huge growth in private car ownership. Although some forms of economic activity have decentralized and new sub-centres have begun to compete with the historic centre, the latter remains the major destination point of a high proportion of journeys. Significant numbers of journeys between sub-centres also pass through the city centre. In response, transport improvements have naturally concentrated on improving communications to the central city. Although similar problems occur in smaller cities, the volume of passengers moving towards the city centre in metropolitan areas is much greater. A good illustration of this can be seen in the case of the underground networks in Mexico City and São Paulo. During rush hour, several central lines carry around 60,000 passengers an hour, the highest figure for any underground system in the world. Despite a recent tendency for economic deconcentration to occur, radial axes from the centre have continued to develop.
(b) Overall congestion levels:
Road capacity has increased to accommodate the growing flows of traffic. Unfortunately, the seemingly inevitable response has been for the number of road journeys to increase. In Caracas, São Paulo, Buenos Aires, and Rio de Janeiro, massive motorway and road programmes soon resulted in new routes becoming saturated. Although the ejes viales road construction programme in Mexico City did reduce congestion for a time, this was very much an exception.
(c) Journey times:
As congestion has worsened, journey times have lengthened. Surveys in Rio de Janeiro, São Paulo, and Buenos Aires all show increasing journey times to key destinations (Camera, 1993; Poole et al., 1990; Brennan et al., 1993). Of course, there is no precise relationship between size of city and journey times. In many cities in developed countries, average journey times have remained constant despite urban expansion through expensive technological improvements. In
Latin America, however, few innovations have been made in the transport sector. With the exception of new metro systems, motorways, and occasional experiments in bus transportation, as in Curitiba, life carries on with little change. As a result, increasing size leads almost inevitably to slower journeys.
Of course, size is only one feature affecting transport conditions. The morphology of the city plays an important part in determining the seriousness of these problems. Equally, the quality and layout of the road system, the level of car ownership, the quality of public transport, and the level of income are all important contributory variables. Nevertheless, size generally worsens the transport situation because it is superimposed upon fossilized road and rail networks.
The traffic problems of smaller cities such as Bogotá, Caracas, Santiago de Chile, Guadalajara, and Pôrto Alegre do not appear to be very different from those of the five mega-cities. Severe congestion sets in well before a city's population has reached eight million people. It begins when the saturation threshold for bus systems is reached and is worsened by the urban land-use structure of particular cities. Certain organizational and management problems are common to most cities in the region, whatever their size. The most obvious similarity is that all are too dependent on road transport. The burden of rising levels of car ownership is growing throughout the region, even if the rate of growth varies from city to city.
The tendency to rely on private cars, buses, and taxis is explained by the lower costs of road solutions in the short term. The longer-term social costs and negative externalities have been ignored and are rarely passed on to users in terms of higher private costs. Apart from lost time and, recently, a tendency for public transport to raise its fares, the majority of these externalities are passed on as social costs. As a result, there has been little sign of improvement in the transport sector in Latin America's major cities; most of the evidence points to worsening congestion, longer journeys, and slower traffic speeds.
It is difficult to say who suffers most from this deterioration. Bus passengers are certainly paying more in terms of longer journeys, and in recent years fare levels have also risen as transport subsidies have been cut. These changes have clearly hit the poor, as the bus is their principal method of transport. But car-owners have also suffered from growing congestion in terms of longer journey times. Their main protection is that at least they can sit in comfort as the traffic crawls along.
The critical question for the future is whether the situation will continue to deteriorate. If levels of car ownership continue to rise and the authorities refuse to place limits on where people can drive, congestion is bound to worsen. There is a clear need for more investment in public transport systems and for their better management; but whether government budgets will be able to bear such costs and whether the private sector can be tempted to invest in public transport are open questions. Deregulation and privatization may help improve public transport facilities, but current evidence is ambivalent with respect to the likely outcome. Certainly, if deregulation and privatization mean that the real costs of public transport improvements are passed on to passengers, then they may hurt the poor. In so far as such a strategy will increase the cost to poor people of getting to work or to local supermarkets, it will clearly reduce their living standards.
Presumably the answers to these questions will vary from city to city and, consequently, so too will the severity of transport problems. For whatever else this chapter has managed to show, it should be clear that despite certain similarities between the mega-cities, there are just as many differences. Traffic congestion may be bad in every large city in the region, but it is still easier to travel around Buenos Aires and São Paulo than Lima.
1. At the time of the survey the metro in Lima was not in operation.
2. There had long been a wish to construct a mass transport system in the city and a detailed plan for the construction of an underground system was first drawn up in 1973. This was designed to relieve pressure on the most congested routes at a time when the city's population had reached 3.5 million.
3. Freeways in the English, not the American, sense are probably the best term to describe the concept. They were not motorways but very wide surface-level roads along which cars and buses could run quickly in a single direction. A large number of homes were destroyed in the construction of these ejes.
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