Transportation II. The pedestrian environment; frontages D. Shopfront and awning; gallery and arcade

Within the urban center and core zones uses mix densely, and the value of land is such that the setback of facades from property lines often diminishes to zero. Private and public realms abut directly. Consequently the details of their design assume heightened importance in the continual negotiation of how each influences comfortable use of the other. Of eight frontages discussed in this series, two are especially characteristic of the most intense Transect zones. The shopfront and awning and the gallery and arcade evolved to mediate between public and private realms. Both are particularly attuned to commercial exchange. The two frontage types entice and protect pedestrians, and simultaneously protect and project the interior activity of a building. When designed properly they add greatly to the usability and interest of civic space. The shopfront and awning is slightly the less urban of the two frontages, essentially because it requires less cooperation from the public right-of-way and adjacent properties. The individual shopfront, its door and display windows at the sidewalk line, offers a cantilevered canopy as shelter to pedestrians. The covering protects the contents of shop windows from broiling in sunlight and stops reflections that render them invisible. A deep awning (and to be effective an awning must be deep) creates a de facto interior below it. Entering the shop becomes easier because one is already perceptually within it; the importance to retail success of such easy transition cannot be overstated. Supported entirely on the private building and often retractable, the canopy is essentially a swift, welcoming gesture. The structure of the gallery and arcade is often, by contrast, neither lightweight nor temporary. While delicate versions exist, it may well be fully architectural, the forms and materials of the building facade projected into a series of posts or piers at its outer edge over the sidewalk. The frontage produces two habitable areas, the arcade below and the open deck or gallery above. Weather protection for pedestrians and the visual rhythm of the posts suggest that adjacent buildings also adopt the frontage. Gallery and arcade naturally spreads across the entire block face. The gallery whose floor is the solid deck above the protected sidewalk may become a private outdoor space for second-level dwellings. Even when residents are not using it, plants, furniture, and lights add interest and variety to the streetscape. In cloudy climates a steel frame and translucent glass deck may be used to provide such space while still admitting light to the sidewalk and ground floor below. In the fullest form of gallery and arcade, the wholly or partly contained sidewalk should be wide enough for pairs of pedestrians walking in both directions to pass each other, while still allowing space enough to pause to look into windows or even set up tables. Ten feet is a minimum; fourteen feet is the most comfortable. Beyond the outer line of posts, there must be two feet for opening the doors of a parked car. Two feet is optimal; more space that that permits the pedestrian to bypass the arcade and thereby ignore the shopfront. William Whyte observed that such frontages often fail commercially when they do not sufficiently overlap the sidewalk. The kinds of structural support — cantilevered for the canopy, trabeated or arcuated for the arcade — are inherently attractive to different architectural sensibilities. Canopies are dependent upon tension members and cantilevers, and thus tend to thinness, lightness, and an emphasis on the knuckly joints between supporting components. They share characteristics with modernist architectural vocabularies. Arcades, with their lines of posts working in compression rather than tension, can run the gamut from thick and sheltering masonry, as in Bologna, to tenuous and elegant metal, as in New Orleans. The expression of weight and the steady vertical rhythms tend toward traditional architectural treatments. Frontages are like cell membranes, selectively permitting passage between building interior and public space as locale and use require. Certain types recur repeatedly across cultures and technologies, and are vital to good urbanism. Frontages deserve time and attention equal to that accorded to building design and to streetscapes.