Overcoming flaws in permeability measures: modified route directness

Abstract

Increased levels of walking have been associated with a range of individual and societal benefits, including reductions in energy use and greenhouse gas emissions, and improved public health. Recent scholarship has sought to provide evidence that good street connectivity encourages walking, and though some correlation is evident, the statistical significance of these studies is generally weak. This paper asserts that the most commonly used methods to measure street connectivity, intersection density and block length, are weakened by random variation, and more significantly, utterly fail to detect street patterns. An alternative measure, modified route directness, is introduced, and shown to be capable of measuring the impact of street pattern on permeability. A more effective measure of connectivity could help demonstrate the correlation between street connectivity and walking, enabling stronger arguments for changes regulatory activity and public investment that supports improved connectivity.