One of the most important aspects of successful “streetscapes” is the amount of activity, diversity, and resulting energy that occurs outside of buildings, usually along or next to sidewalks. Pedestrians strolling along tree-lined sidewalks fronting cafes with outdoor seating and storefronts of various businesses is the model for which most city planning departments now strive—and few could argue that this isn’t a desirable goal for virtually any municipality of any size. So what are some of the things, the design considerations, that make this model successful?
First and foremost is the size and shape of the outdoor space (some call the “outdoor room”) of the street/sidewalk. This space is determined by the width of the street and sidewalk in proportion to the height of the buildings that line it. Some have suggested that the height of the surrounding buildings should be around 2/3 the width of the street–I have found this to be generally correct. There are other influences, like mature street trees, and many exceptions, but in any case, the comfort of the pedestrian or the person sitting at an outdoor café will generally be greatest when there is a sense of “enclosure” formed by the surrounding buildings. Rarely is this possible with one story buildings or with streets that are too wide. This comfort level is very important because even if there is an attractive outdoor café with outdoor seats, no one will want to sit there if it feels exposed, out of scale, or non-welcoming.
In addition, no one will want to be there if cars are speeding by just a few feet away from the tables. This is not to say all such areas have to be car-free zones (such as the beautiful Belden Alley in San Francisco pictured above) . Non-threatening auto traffic can actually add to the vitality and energy of the sidewalk activities. The car speed has to be controlled by narrow enough streets. And curbside parking, in addition to slowing traffic, can form a comfortable separation between sidewalk activity and traffic. Unfortunately, the opposite is what we find in many new developments, all in an effort to allow traffic to move faster, without interruption, at the expense of the pedestrian user.
Next: Street Vitality 2: Urban Landscaping