The OSCADY model calculates capacities, queues and delays for isolated (uncoordinated), traffic signal-controlled junctions. It can evaluate a set of known signal timings, and optionally it can optimise stage lengths and/or cycle time to minimise delay. More recently, an extension to the simulation mode allows the performance of simple adaptive signal control to be estimated.
The signal optimiser in OSCADY is stage-based, but signals data is set up by allocating phases to traffic streams and then adding stages in a similar way to TRANSYT 16. Stages and stage sequences can be generated automatically based on phase allocations and an Intergreen matrix.
What does OSCADY model?
OSCADY is intended to be used at relatively simple signalised junctions (or temporary signals at road works) where the emphasis is on setting up model runs quickly and easily, but can model junctions that include flared approaches and opposed right turns. Its integration with ARCADY and PICADY means that users can switch a junction between priority and signalised options and compare the results within one package.
Data input such as traffic demand OD matrices takes the same form as that used by the ARCADY and PICADY. Other tools such as; reports, analyser tools, junction diagrams and file handling will also be very familiar to users of ARCADY and PICADY.
Optionally, signalised junctions can be evaluated in Lane Simulation mode which offers additional functionality, such as the ability to model intermittent stages and partially signalised junctions, including signalised roundabouts. In Junctions 10 the simulation mode capability has been extended to allow the performance of simple adaptive signal control to be estimated. This model can be applied to temporary signals (such as at roadworks) and some control over the controller logic is provided in order to mimic behaviour whenever there is no demand at any point within the modelled time period.
Basic junction structure and signals data can be exported to TRANSYT. A file can be started using OSCADY and then transferred to TRANSYT should there be a need to use the more advanced features available in TRANSYT.