Evaluating Street Quality for Walkability from 3D Models

Abstract

Street quality is critical to urban sustainability. Well-designed streets encourage walking behaviour and attract public activities, thus advancing the sustainability of a city as a whole. Currently, most quantificational analyses of street quality are based on two dimensional maps, using network algorithms and economic theories to calculate accessibility and land value or to account for a series of elements such as number of trees and number of courtyards in order to audit quality scores. The analysis from three dimensional models and human-centred views is rarely utilized but could offer new possibilities to provide urban planners and designers with analytical feedback on the built environment and design process. This research explores ways to relate physical features with walking behaviour using Reid Ewing's Urban Design Tool to measure the street quality for walkability. It applies physical metrics from measuring parameters in 3D models based on the human's perspective and other building metrics from GIS data online to systematically audit street walkability. To validate this method, we take two separate studies. One is a case study to evaluate the street walkability of two districts in NYC from their 3D models and GIS data and to visualize the scores. The result from digital models and real environment are similar which indicates the feasibility of applying this method in urban scale. The other is a pilot study asking a group of students (N = 8) to evaluate street walkability of 3D models, telling them the scores calculated by this method, to explore how the scores influence their evaluations. This study illustrates the possibility to quantify the evaluation of street quality for walkability using Urban Design Tool in 3D models to inform urban designer's evaluation in street scale during the design process.