The greatest new development in traffic engineering since the traffic signal?

A triple conflict between traffic streams – for instance, an appreciable right-turning flow, as well as heavy straight-through flows – is often the key factor leading to limited capacity and high delay at a junction, either three-legged T or four-legged crossroads. It is, however, possible to design a junction so that such a conflict is replaced by three lesser conflicts, each between only a pair of flows. This leads to higher capacity and less delay, for a given amount of road space. Such designs have been publicised by R. Goldblatt, F. Mier, and J. Friedman. The present contribution draws attention to support given by T P. Hutchinson's article in Traffic Engineering and Control in 1974. That support was based on queueing formulae and numerical calculations using them.