Chapter II: The theoretical basis

Three variables

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So, with respect to any environmental area, the traffic problem can be approached in terms of three main variables—the standard of environment, the level of accessibility and the cost that can be incurred on physical alterations. These can be related in a rough and ready ‘law’. It is that within any urban area as it stands the establishment of environmental standards automatically determines the accessibility, but the latter can be increased according to the amount of money that can be spent on physical alterations. In plain words this means that if it is indeed desired to have a great deal of traffic in urban areas in decent conditions it is likely to cost a great deal of money to make the necessary alterations. The idea that any urban area, as it stands, has a definable traffic capacity if the environment is to be secured, is very important. There is really nothing strange about it. A factory is designed for so much plant and so many operatives; a school is designed for so many children; a house will hold so many occupants and if more are crammed into it, it becomes a slum. There is some elasticity in capacity, but not much. All that is being said here is that exactly the same kind of rule must apply to an area occupied by buildings and the amount of traffic it can decently contain.

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The capacity of an environmental area to accept vehicles moving and at rest depends largely on the way the buildings and access ways are arranged. The example has already been given of a residential area with narrow conventional streets, which would have a low capacity. Another example would be a complex of conventional shopping streets with show windows facing pavements in the usual way—an arrangement which still works fairly well provided there is very little traffic. In both cases it would be possible to re-arrange the accommodation in ways that would enable many more vehicles to come in and yet give an equally good or perhaps much better environment. In the case of the shopping area, for example, the shops could be re-arranged so as to front on to squares or streets reserved for pedestrians only, with the vehicular access for goods vehicles and parking at the rear. Or there could be parking on roof tops, or there night be a central multi-level traffic core with the accommodation set out to the flanks.