A survey of quasi‐synchronous P.R.T. interchange control algorithms

A selection of interchange control algorithms representative of three broad categories of control strategy has been developed. The need for a preliminary comparative evaluation based primarily on abort‐response is shown to exist; this study is subsequently performed.

It is concluded that strategies which require manoeuvring in the interchange ramp area but schedule these manoeuvres while the vehicles concerned are in the pre‐switch area are superior for numerous reasons. A new strategy of this favoured class is introduced. This algorithm utilizes the already proven “loop‐forming” mechanism to permit queueing of diverted vehicles, for an indefinite period, within the interchange. Moreover, unlike any other known strategy, of this category, the algorithm in question incorporates a multi‐level vehicle priority handling scheme.