Developments in the SPA model of efficient vehicle progression at signalised intersections

The Simple Platoon Advancement (SPA) model describes a system where the roadway infrastructure controls vehicle progression through intersections. The objective is to increase - compared to traffic behaviour of today -the throughput of vehicles primarily from a stationary queue through the junction without resorting to a greater rate of acceleration than is used by today's drivers. Progression is achieved by the queue being moved as a single unit (a technologically-connected platoon) with instant start on green and uniform acceleration. A platoon dispersion mechanism allows the control of the vehicles to be safely transferred from the infrastructure to the driver of each vehicle. The model was introduced at CAITR99 as the Simple Queue Discharge Model and refined in 2001 to become the Simple Platoon Advancement (SPA) model. This paper extends that work to study the effect of a SPA system on intersections.