"Narrow streets, if they are not too narrow (like many of Boston's) and are not choked with cars, can also cheer a walker by giving him a continual choice of this side of the street or that, and twice as much to see. The differences are something anyone can try out for himself by walking a selection of downtown streets.
This does not mean all downtown streets should be narrow and short. Variety is wanted in this respect too. But it does mean that narrow streets or reasonably wide alleys have unique value that revitalizers of downtown ought to use to the hilt instead of wasting. It also means that if pedestrian and automobile traffic is separated out on different streets, planners would do better to choose the narrower streets for pedestrians, rather than the most wide and impressive. Where monotonously wide and long streets are turned over to exclusive pedestrian use, they are going to be a problem."
-Downtown is for People (1958)I'm not sure if we ever learned which Boston streets Jacobs considered too narrow (surely not Acorn Street!), or if that was an opinion she later changed, but the arguments stand nonetheless. One concrete example is also provided:
"The real potential is in the street, and there are far more opportunities for exploiting it than are realized. Consider, for example, Maiden Lane, an odd two-block-long, narrow, back-door alley in San Francisco. Starting with nothing more remarkable than the dirty, neglected back sides of department stores and nondescript buildings, a group of merchants made this alley into one of the finest shopping streets in America. Maiden Lane has trees along its sidewalks, redwood benches to invite the sightseer or window shopper or buyer to linger, sidewalks of colored paving, sidewalk umbrellas when the sun gets hot. All the merchants do things differently: some put out tables with their wares, some hang out window boxes and grow vines. All the buildings, old and new, look individual; the most celebrated is an expanse of tan brick with a curved doorway, by architect Frank Lloyd Wright. The pedestrian's welfare is supreme; during the rush of the day, he has the street. Maiden Lane is an oasis with an irresistible sense of intimacy, cheerfulness, and spontaneity. It is one of San Francisco's most powerful downtown magnets.
Downtown can't be remade into a bunch of Maiden Lanes; and it would be insufferably quaint if it were. But the potential illustrated can be realized by any city and in its own particular way."
-Downtown is for PeopleNow, Maiden Lane is an example of the "old urbanizing" of the 19th century speculative grid: the process in which large grid blocks along wide streets were subdivided by lanes of more human, and less wasteful, dimensions. It was a process which occurred in nearly all cities of that era and plan, but nowhere more notably than in Melbourne. Still, as you can see, Maiden Lane is not a "really narrow street," in Nathan Lewis' terminology, but of a width that is comparable to the major commercial thoroughfares of late medieval and Renaissance-era cities. It is only narrow by comparison to the typical urban street laid out by the 19th century grid-makers (and in fact Jacobs' article mentions only American examples).
Jacobs later made additional observations implicitly supportive of narrow streets in car-free contexts:
"Paving which merged roadbed and sidewalk would probably induce more pedestrian use of roadbed space .... However, that is apparently only part of the answer. In suburban shopping centers where "streets" are wide but thoroughly pedestrian and without curbs, people stay to the sides also except where something interesting to see has been deliberately placed out in the "street." It takes tremendous numbers of pedestrians to populate the whole width of the roadbed, even in scatterings. The only times pedestrians seem to use, or want to use, a street roadbed in this fashion are in cases of extraordinary floods of pedestrians, as in the Wall Street district or the Boston financial area when the offices let out .... In more ordinary circumstances, people are attracted to the sides, I think, because that is where it is most interesting."
-The Death and Life of Great American Cities, p. 452-53Jacobs was not the only urban thinker of this era appreciative of narrow streets (Bernard Rudofsky and Kevin Lynch had similar things to say, using more frequent reference to foreign examples), yet Jacobs stood out for looking past aesthetics to grasp the universal logic of urban form and human behavior that made places like Maiden Lane work so well.
*Raymond Unwin in 1909's Town Planning In Practice made several references to the aesthetic merits of narrow streets in medieval towns, and even criticized the minimum street width ordinances of his day, but did not dwell on these streets' urban functionality (and, ultimately, did not take literal inspiration from them in his own designs, indicating that he did perhaps see them as functionally obsolete).