Angular integration is the reciprocal of the normalised angular total depth. It can be compared across systems. It measures how close each segment is to all others in terms of the sum of angular changes that are made on each route.
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