An overview of the methodology of the traffic adaptive signal control method BALANCE is provided. The method is intended for complex urban road networks, particularly where it is intended to prioritise public transport. Current requirements for flexibility and compatibility include modularity, protection against component failure, extension irrespective of the original configuration and integration using hierarchical system architecture. The basic structure of BALANCE is outlined. It may be applied to a single junction or to a complete urban network. The microscopic traffic model used in the method calculates the positions of the vehicles approaching junctions at one-second intervals. The data from the microscopic models are aggregated and origin-destination streams determined. The control model uses a cyclic approach. A field trial and simulation studies of BALANCE were carried out in Munich, Germany and a revised version was tested in London and Glasgow, UK. The Munich trial showed a 14% reduction in car traffic delay and a cost:benefit ratio of 1:19. In the London trial, average car delay was reduced by 4%.
Abstract