An analysis of the urban design qualities of two streets, based on the works of Allan B. Jacobs, Jan Gehl, Edmund Bacon, and Kevin Lynch.
Collins Street, Melbourne
Collins Street is a major commercial thoroughfare in the heart of Melbourne’s Central Business District (CBD). This street incorporates all of Allan Jacobs’ “requirements for great streets” as well as the majority of extra “qualities that contribute”.
There is plenty of sidewalk space for people to walk with some leisure, only getting as crowded as roughly 7-9 people per minute per meter during the daytime (ideal to allow for all paces). Many street trees placed relatively close together provide shade in the summer for physical comfort as well as the lighting variability that acts to engage the eyes. There are many skyscrapers along the street providing a clear sense of definition and maintaining complementarity, but retail awnings never taller than one or two stories allow the street to still feel human scale. There are plenty of doorways and windows providing transparency into the many diverse types of shops as well as full arcades serving as intriguing diversions (that Edmund Bacon would suggest intentionally guide people between blocks). A high level of maintenance and quality of construction/design is also apparent, as it is clear both the city and individual store owners are quite keen to promote this as the premier shopping street in the city.
It is well-connected to many landmarks & attractions in the area and is anchored with major destinations (a railway station and public gardens) at its beginning & end. Many design details such as benches and small plazas provide for places to stop and rest along the way. It is also fully accessible by public transit (trams) running along the center of the street and on cross-streets. There is limited parking available but it is not relegated to large lots, so storefronts remain oriented towards the street itself.
This street succeeds at Jan Gehl’s defined “assembling” of people and activities on the full spectrum from small to large scale. Functions are effectively located to face the street, the distances pedestrians need to walk are short, and all elements are dimensioned appropriately. The street façade has narrow units and many doors, keeping small retail units highly visible and inviting while hiding the massive offices above. Soft edges with open storefronts facilitate a frequent exchange of people in and out of shops.
Taraval Street, San Francisco

This is a typical residential street with a small number of retail establishments in the Sunset District of San Francisco. It follows design patterns that closely match Jan Gehl’s definition of “dispersion” and hence there is not much active street life on most days.
This street is a mostly car-centric throughfare, with large lots and a segregated structure (i.e., little mixed-use development). The street itself is extremely wide, resulting in an overdimensioned area that is not appealing (or safe) to walk across for pedestrians. While the homes themselves have reasonable façade widths, they are almost always fronted with a parking garage as opposed to any kind of soft edge (i.e., no front yards, gardens, or other kinds of staying areas that could facilitate the flow of activities between the inside of the home and the street). The result is that residents spend practically no time directly in front of their houses and hence there is very little interaction between neighbors.
Allan Jacobs would not consider this a “great street” as it misses many of the required criteria. The lack of trees or other shelter makes for poor physical comfort, the lack of transition zones and distances between entryways reflects low transparency, the monotonous building design with few breaks in the façade results in few qualities that engage the eyes, and the low building height to horizontal distance ratio makes for a weak sense of definition. However, this street does feature complementarity with its repeated architectural style and a reasonable level of construction/design quality and maintenance (perhaps made easier with the lack of frequent activity).

The light rail line running along the street (as well as the ample space provided for automobiles) suggests that the primary purpose of this street is to facilitate movement. It’s designed for Kevin Lynch’s definitions of “persons traveling” and “flow facilities” while the spaces for “persons acting” are primarily behind closed doors.