Bridges as walls The biographer of Robert Moses, Robert A. Caro, refers to the bridges and underpasses of the famed New York State parkways. These bridges and underpasses are quite low, intentionally specified by Moses to allow only private cars to pass. All those who traveled by bus because they were poor or black or both were barred from the use and enjoyment of the parkland and its "public amenities" by the technical design of the bridges. Even at the time of Robert Moses, a political statement of the form "We don't want them blacks in our parks" would have been unacceptable in New York State. But a technological expression of the same prejudice appeared to be all right. Of course, to the public the intent of the design became evident only after it was executed, and then the bridges were there. Ursula M. Franklin, The Real World of Technology politicsclassracediscriminationurbanism
Paths, edges, districts, nodes, landmarks The contents of the city's images which are referable to physical forms can conveniently be classified into five types of elements: paths, edges, districts, nodes, and landmarks. Paths are the channels along which the observer customarily, occasionally, or potentially moved. Edges are the linear elements not used or considered as paths by the observer. They are the boundaries. Districts are the medium-to-large sections of the city, conceived of as having two-dimensional extent. Nodes are points, the strategic spots in a city into which an observer can enter, and which are the intensive foci to and from which they are traveling. Landmarks are another type of point-reference, but in this case the observer does not enter within them, they are external. They are usually a rather simply defined physical object: building, sign, store, or mountain. Kevin Lynch, The Image of the City City districtsAs a kind of gateway cities