Measuring oppressiveness of streetscapes

Oppressiveness, as experienced in urban environments with high-rise buildings, is a form of environmental stress that poses psychological pressure on urban residents. The intention was to study the oppressiveness of streetscapes and provide a tool that urban planners could use to measure oppressiveness to then subsequently improve the livability and pleasantness. The benefits of this tool were assessed through a dialog with five planners and also as a specialist determination by the authors. The influence of trees lining a street in front of buildings was assessed in Tokyo to advance the development of an equation initiated by previous researchers aiming at measuring the oppressiveness. The measurement was done by solid angles of physical elements of street.In the controlled environment of an experiment room, we had the opportunity to more precisely study the influences of tree, buildings, sky, and their inter-relationships on human psychology. Physical parameters of the 3D-generated scenes were able to be adjusted based on characteristics in the real urban environment. Oppressiveness significantly increased when the solid angle of the building was enlarged. Trees revealed a significant mitigating influence on the oppressiveness and the portion of trees covering the building façade had the most impact on lessening oppressiveness. The following equation was developed through correlation analysis to estimate the oppressiveness of streetscapes: ω = Σ{(ΩB − ΩTCB)Γ3} where ω is the oppressiveness, ΩB is solid angle of building facade, ΩTCB is solid angle of trees covering building, and Γ is the distance of viewer from the building complex.

► We aimed to provide planners with a tool to measure oppressiveness of streetscapes.
► We measured oppressiveness using solid angle of physical elements of street.
► Tree portions that covered building facade had the most mitigating effect.
► ω = ∑{(ΩB − ΩTCB)Γ3} was developed utilizing correlation analysis; ω is oppressiveness.
► ΩB and ΩTCB are solid angle of building and trees covering building, Γ is distance.