reducing natural green space in residential environments. The basic idea is to keep rainwater on the site for growing vegetation or local infiltration, thus preserving much of the natural water cycle. This is accomplished by open swales and ditches, restraints on surface flow, and small but many impounding basins. There are maintenance issues, but the concept holds water in more ways than one. Not too many actual examples exist yet, but plenty of low-density designs point in this direction. Literature too is available. The thrust of this discussion is to go a step further yet—to advocate reduced streets (another, rather unfortunate term has also appeared—“skinny streets”), which has not been tried yet in actual practice. It is based on the observation that traffic volumes on local streets are extremely low (perhaps a dozen cars per hour). It is, therefore, absurd to build 28 or 36-foot wide traffic ways, which are expensive and hardly used. One lane should be enough, and, if two vehicles face each other, one of them can pull over. Indeed, even a fully paved lane is not necessary -- two paved tracks spaced for the wheels of automobiles and trucks should suffice. Obviously, there is a need for strong enough surface in the middle and at least on one side to accommodate vehicles that have to veer off the tracks. This auxiliary surface can be porous (paving blocks, for example) with grass growing through. The reduced street represents traffic calming at a basic level, and it can be much greener that the design described above. It is also in violation of land development ordinances and subdivision regulations in just about every American municipality. Presumably this can be changed, and a truly harmonious living environment achieved. A prerequisite for making this concept work is limiting the size of such auto-restricted zones. Motorists will become impatient if they cannot reach streets within a reasonable distance where rapid progress can be made. This is also a significant consideration for service vehicles and especially emergency equipment. Arterials How to handle arterial roadways in well planned cities is the most difficult design problem. They have to accommodate large volumes of motor vehicles, which move quite fast, but they also have to come in close contact with residential and office buildings, with public spaces and major destination points. They are not and they cannot be very people-friendly, because they are basically vehicle facilities. At this level separation 2005 Roma Street VIDEO ANALYSIS Timothy Zeith
is justifiable, but arterials must be directly connected to the adjoining territories they serve. Also, since every city must have quite a few miles of arterials, extraordinary capital expenditures (such as depressing or elevating them) are not reasonable expectations. It appears that the best solution is nothing less than the urban and urbane boulevards that were invented in mid-19th century Paris. Although not designed for motor traffic, they adopt themselves splendidly to contemporary needs and city structures. The basic configuration is a central, multi-lane, two-directional roadway with or without a median, flanked by landscaped separators that accommodate pedestrians, followed by one-directional service roads on each side that provide access to abutting properties. Originally, the boulevard was the focus of community life; today it has to be seen as a separator of districts and neighborhoods because crossing it on foot requires some effort and caution. Also, if it is of adequate width, activities on one side cannot really be seen from the other, and they do not interact very well with each other. The outside edges of a boulevard in a dense city environment will be lined with shops, eating and drinking places, community facilities, and institutions because of accessibility. Thus, such networks define a neighborhood or district structure with the service establishments on their “outside”—a crust. This concept agrees quite well with the residential enclave design described previously. But not every arterial can be a boulevard, not even in Paris. There will have to be a network of regular major streets with the principal task of carrying motor traffic. As the options to provide the various amenities of a landscaped boulevard decrease, the more the presence of people and service establishments have to be minimized on such a street. The result can be an arterial that simply consists of multiple fast lanes. In those cases, good design would introduce buffer strips on both sides and eliminate parallel sidewalks, thus precluding establishments with direct frontages on the arterial. The neighborhoods then become inner-oriented with services placed inside on collector streets. This is the “classical” model of city spatial organization, recommended almost unanimously since the 1930s.
The amount and ferocity of criticism that strip malls have received is massive—they have been called anti-urban, ugly, and unsafe. They can be called anti-urban only in the sense that commercial strips do not follow earlier, well established models. Ugliness is in the eye of the beholder, and, without venturing to explore this aspect in length, there is the Las Vegas aesthetic to consider. Safety certainly is a concern, but several improvements can be added: well separated service roads from the main channel for maneuvers, weaving, and sign reading; carefully designed entry and exit slips; and overpasses at regular intervals for U-turns. Major Highways Limited-access highways respond to the movement needs of fast motorized vehicles almost perfectly, but they also create the heaviest impacts on the urban environment. These facilities were invented and developed in the 20th century, and it is hard to think of any new engineering improvements to the more recent examples that would be useful— except for safety devices and acoustical walls that are now being added in many places. Automobiles and highways (interstates, Autobahnen, autostrada, autoroutes, etc.) are made for each other, and that combination has extended personal mobility to an unprecedented degree in developed counties, with the developing ones trying to catch up. The Interstate Highway System of the United States, which forms a complete network connecting all sizable centers, is credited with having all the essential underpinnings for the most efficient production and distribution system. The problems occur when these highways enter built-up territories. Originally, they were seen as solutions to urban problems and the presence of slums; they turned out to have very serious and destructive impacts on the urban environment. By cutting wide swaths
SITE DOCUMENTATION UQ 127
The Strip Mall Most major roadways radiating out of city centers in North America and Australia are lined with rows of separate business establishments that cater to motorists (or at least expect that their customers will arrive in an automobile) and attempt to draw their attention by large, bold, and colorful signs.
These facilities were never planned as such; they just happened because they respond admirably to contemporary needs for efficient distribution of goods and retail. Functionally, there is not much difference between strolling along a cozy shopping street and looking at shop windows and driving along at a fast clip on these roadways observing signs until sighting one that offers the desired service. The first is a very agreeable experience and one has to hope that it will always be available in civilized cities with a sense of history; the second is most effective in reaching a specific large retail place where a wider choice of goods and better prices will be available than in a mom & pop store. It is a winner, both for shoppers and retailers, but not for moms and pops.
Published on Aug 5, 2010
Published on Aug 5, 2010
Arterials How to handle arterial roadways in well planned cities is the most difficult design problem. They have to accommodate large volume...