Segment angular integration measures how close each segment is to all others in terms of the sum of angular changes that are made on each route. It is measured as the reciprocal of the normalised angular total depth, allowing it to be compared across systems.
Segment angular integration
Hillier , B. & Iida, S. (2005), Network and psychological effects in urban movement, In: A.G. Cohn and D.M. Mark (Eds.): COSIT 2005, LNCS 3693, pp. 475-490.