freeways and railyards

Rivers and ravines are extended linear elements in the city. They are relatively impassable, make no territorial infringement on their surroundings, and are experienced primarily from their edges; they are pastoral backdrop. Rivers and ravines are attractive natural occurences and are usually considered a positive part of the urban fabric. However, they have a side-effect which is not always beneficial: they divide different parts of the city. Becasue they are an attractive part of the environment, we tend to accept their divisive character and try to take advantage of the urban forms they dictate - often with great success.

Main rail yards and superhighways, too, are extended linear elements in the city. Though passed along, they are impassable to those who live alongside - who experience them from their edges. Their users are sealed off from and indifferent to those alongside, and, though they may be a nuisance, they make little territorial infringement upon those alongside. There is little question that main rail yards and superhighways are divisive elements in the urban fabric. They are hardly pastoral, yet little seems to distinguish them structurally from rivers and ravines.

What does distinguish them is primarily historical and aesthetic: Railyards and superhighways are divisive, harsh, and man-made (hence avoidable). Rivers and ravines are divisive, usually attractive, gentle, and natural (hence inevitable). In order to incorporate railyards and super-highways in the modern city the trick seems to be to capitalize on their structural similarity to rivers and ravines - yet to minimize their negative impact on their surroundings. (The biggest trick will be not to have to incorporate any more such elements into our cities, or to remove the ones we have - Boston’s “Big Dig.”)

One way of dealing with rivers and ravines when they prove undesirable (usually to real estate interests) is to make then disappear: covering them with culverts, soil, streets, and buildings. This, in the long run, is probably the most commendable solution to main rail yards and superhighways in the city. It is, however, expensive, and requires a very high demand for new urban land. (Examples of such burying in fact abound - in the world’s largest cities a surprising amount of rail and highway has been pushed underground, and a number of projects are in planning and construction. )

Making rivers and ravines disappear is rather extreme, and it is certainly more typical to live alongside them. Rivers and ravines are normally bounded either by public network or by private domain:

Both of these situations seem acceptable. In the first the streets which give on to the pastoral backdrop are one-sided and suffer some lack of urban intensity. The territorial marking, however, is clear - and any loss in symmetrical street activity is made up for in natural beauty and spatial relief. The second situation, where most often the private open space of the private domain meets the pastoral backdrop, is different mainly in that all streets retain their unifying character - they are always the two-sided locii of human interaction, and movement.

This difference becomes very important when we insert superhighway in place of sylvan ravine: When “pastoral” backdrop is not an element of gentle relief but a large, harsh no-man’s-land in the middle of the city. If protective-presentational boundary and streets surround a superhighway the superhighway has an exaggerated presence in the urban fabric; the normal pattern of two-sided streets is interrupted as two one-sided streets face each other over a giant void.

If, instead, the superhighway is surrounded by private domain, neighbouring local streets are continuously bounded by protective-presentational boundary and retain significance and intensity as the locus of public and private contact. The result is that the interrupting element is buried within the city block and local streets are allowed to retain their own normal urban significance.

artery vs. expressway

Rail yards and cross-town expressways are extreme examples. Simply by being sunken or raised above ground level such facilities are certain to be divisive non-streets. At ground level, however, questions of degree begin to arise. Even at ground level, a wide rail yard with stored trains and large numbers of tracks is impassable and divisive. Yet a ground level 3-track-wide rail line which is occasionally used for train storage, which can be easily crossed, and which has a local depot can be a positive part of the public network. A 12-lane limited-access cross-town expressway at ground level is no more unifying than one which is set twenty feet in the air. Yet there are many examples of 8-, 10-, or even 12-lane streets with fast-moving traffic, regular intersections, and traffic control. Such arterial routes can carry a surprisingly high volume of traffic. The important thing about such routes is that they are real 2-sided streets defined by the protective-presentational boundary of bounding contributing activity. (Eg., the Champs Elysees, Paris; Park Avenue, New York; Avenue Road, Toronto.) Though children may not play in such streets, and though crossing them may be done with some regard for one’s safety, they are not divisive canyons in the city’s fabric.

When major routes are inevitably divisive by-passes it is best to “turn our backs on them,” ”burying” them in the centres of large city blocks - thus allowing local streets to have a life of their own. However, when it is possible to break down major routes, or “tame” them to their surroundings, by introducing regular local pedestrian and vehicular access and traffic control, and by introducing surrounding activities and protective-presentational boundaries, such action should be taken. What are now divisive ground level limited-access expressways might one day be marvellous arterial boulevards: Boulevards which are the uniting commercial and leisure focii of surrounding neighbourhoods and regions.

These last two discussions may have appeared peripheral to the main line of argument of this essay – and to some extent they are. However, with the structural understanding of [block/public network/pastoral backdrop], major streets, throughways and rivers can be seen as integral parts of the city’s perceptual and territorial framework. And this lens can help clarify future decisions about how these large-scale realities are best incorporated – and least damaging to the life of the city.