The necessity of adjustments I. The alley A. The alley offset

The last two decades have witnessed a heartening revival of traditional planning techniques. Element after element, the components of walkable, mixed-use, civically conscious environments have been restudied, redeployed into use, and gradually have gained widespread acceptance on the part of the public and even of non-new urbanist professionals. But the restoration to legitimacy of traditional planning elements has proven not to be a static situation. Every traditional element is subject to the changing pressures of its contemporary context. Consequently the shape, size, relative location, and appropriate character of elements must constantly be restudied. That is the cultural and technical paradox at the heart of New Urbanism; tradition must be continually reset in order for it to serve its original purpose. An example of such recalibration is the rear alley. Twenty-five years ago merely proposing the use of a rear alley system in a new development was a radical proposition. It sufficed to model it on the standard alley configurations evolved prior to the wholesale change of planning practices that began around 1930. A pattern of H-alley blocks, with occasional I-alley blocks, and T-alley blocks where use-mixes changed, usually overlaid first-generation new urbanist plans in a regular way. In particular, alley outlets onto the regular street network most often occurred opposite each other on block faces. changes in automotive type and technology The intervening years have seen the introduction of SUVs, larger in size and turning radii, and improved suspension systems in vehicles in general, which, for better or worse, allow higher-speed turns. At the same time, once the existence of an alley system became legitimate, it became subject to the scrutiny and ever-escalating design “needs” of various kinds of service personnel. Such technical and regulatory changes have tended to produce ever wider and more elaborate alleyscapes. In theory still just locally utilitarian, alleys have moved towards the condition of regular thoroughfares, with attendant problems of speeding, parking abuses, and vehicular dominance. Beyond that, there are the confusions of urban navigability and social behaviors that result when public and semipublic ways become nearly indistinguishable. To retain the original compact, complex, slower-paced usefulness of the rear alley, additional techniques are essential. Among them are deliberate discontinuities in the alley system. “Hiccups” in the alignment of alley outlets — the alley offset — and other techniques (to be discussed subsequently) should be held in ready reserve when designing a neighborhood’s service system. Their use is indicated whenever circumstances are inducing the baroque elaboration of the alley system just described. The alley offset — “misalignment” of alley mouths between blocks — need not be large to be effective. It must be adjusted with the width of the street being crossed by alley-to-alley traffic so that it is impossible to slalom rapidly from one alley to the next. In general, the mouth of the next alley ought not to be visible when traveling down one; neat “enfilading” is to be avoided. In addition, on-street parking should not be removed opposite alley mouths. The nonsystem system of alley offsets produces building sites whose special circumstances should be recognized. The structures situated opposite alley mouths are presented with problems and opportunities. They have longer views than their immediate neighbors, but perhaps of less pleasant scenes and with headlights an annoyance at night. They terminate vistas, and there will be a consequent tendency to elaborate their facades and silhouettes beyond those of otherwise similar neighbors. Appropriate coding of such lots can remind people of the situation and suggest responses to it. The next installments of The Technical Page will discuss further examples of altering alleys and other traditional elements in order to adapt them to contemporary circumstances