Of the all of the scenarios across the six planning tools and eight building shapes, twelve are more livable with overall livability index values over 0.52 (Table 11). All the twelve scenarios area variations of tower shape buildings across three planning/design tools, consisting of stair-shaped setback (i.e., SSB_3_1, _1, 3_2, 2_2, 2_4), large building setback with floor area shift to the top (i.e., SB-T6 and T4.5), smaller building coverage percentages (i.e., BCR-30%, 35%, and 40%), and
increasing backyard depth by shifting floor area to top (BD_T5.5, and T_4.5). Of all these scenarios, streets come along with greened sidewalk on both sides the whole length. These scenarios vary in indexes of livability aspects, but generally derived from the tradeoff between leaving more open space on the street level and leaving space in the sky by lowering buildings, and hence reflected on the tradeoff between such sky-based aspects as sky view and such ground-based aspects as viewshed.
Table 11 Most Physically Livable Scenarios
Scenario
Factor Solar Radiation Viewshed
Percentage Average
4. Conclusions and Policy Implications
This paper examines the impacts of the tools on livability, generally employed by urban planners and/or designers. Through simulation analysis in a hypothetical dense community, the roles of a range of eight planning/design tools are revealed in affecting livability in the regards of visible horizontal space, breeze way, visible sky, Radiation, and residential privacy. The results suggest that overall, reducing BCR decreasing BCR brings space to the ground at the cost of more building mass in the sky may be worthy since the magnitudes of beneficiary visible horizontal space, breeze way, and privacy is larger than that of loss of visible sky and Radiation on the one hand, and the level of sky view and Radiation seems at a higher level than visible horizontal space and breezeway, which may lessen the negative impact but weighting the positive gain. Besides, more space on the ground provides the potential of more green open space within close proximity to pedestrians, as well as plants, insects, and birds. Building setback plays the role of moving space from backyard to front yard, and hence enhances both ground-based and sky-based livability at the front of the building at the cost of less space in the backyard. It can be a more politically feasible tool since it adds no extra cost to developers, as opposed to lowering BCR resulting in higher cost due to taller buildings, and provides more space along the street, which is tangible to all users. However, the impacts in terms of
downgrade of Radiation, breeze way, privacy in the backyard, which is barely measured in the paper, cannot be ignored, and deserver further analysis.
In addition, in pursuing certain aspect of livability, the most effective tools are also identified, which may be applicable in different urban settings. In a neighbourhood where visible space on the ground or breeze is of most concern, or even providing more space for eco-community, low BCR is the most effective tool to adopt, and building setback but shifting floor area to the top of the building, and the conventional building setback come after. Furthermore, in a neighbourhood where visible space in the sky or Radiation is of most concern, building setback and increasing BCR are the two most effective tools. To pursuing residential privacy alone, p reducing BCR, back setback and setback and shift up tools are the top three effective tools.
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