Junctions 9 is the latest version of TRL’s industry-standard package for the modelling of roundabout and priority intersections.
Junctions 9 consists of ARCADY 9 (the Roundabout Module), PICADY 9 (the Priority Intersection Module), and OSCADY 9 (the Signalised Intersection Module, available in Junctions 9.5 onwards). These modules are sold and licensed separately.
The junction diagram includes tools to help with the measurement of standard and mini-roundabout geometries, such as entry width, flare length, entry radius. These work by providing a set of control points and construction lines which can be dragged to coincide with the appropriate points on a background image or drawing of the junction. Junctions 9 uses these control points to calculate the ARCADY geometries which can then be automatically saved in the file.
Data from the original mini-roundabout model (first introduced in ARCADY 5) has been re-analysed and as a result a revised model is now available. In typical cases, this tends to predict slightly higher capacity. Data input is identical to previous versions.
The Audit Trail system provides a way of tracking the version history of the file, which is especially useful for complex files or when a file is worked on by several people. Junctions 9 can optionally record each change made to the file, forming a log of all changes. The same system also allows users to manually enter the overall status of the file.
If TEMPRO datasets are installed, Junctions 9 can be used to calculate traffic growth factors. Simply enter the base/future years, geographical area and other properties and J9 will read data directly from the TEMPRO datasets and produce a local growth factor which can then be automatically applied to Demand Set relationships.
Junctions 9 can be set up to read traffic survey data direct from Excel spreadsheets. This works across demand sets and time segments, and can apply to turning counts and HV% information. Once set up, this provides a quick way to transfer demand data from Excel into J9 and can significantly reduce the required amount of data entry.
It is now possible to use Lane Simulation to model PICADY T-junctions.
The lane structure is set automatically, based on the normal PICADY junction properties.
Zebra and pelican crossings can be modelled on any arm, for all arm types. For example, you can now model crossings at the same time as blocking, and other combinations which were previously not possible.
The visualisation and animation tools first introduced in J8 can now also be used at T-junctions.
The OSCADY module for signalised junctions, introduced in Junctions 9.5, allows evaluation and optimisation of signals at simple isolated signalised junctions. Signals data can be exchanged between Junctions 9.5 and TRANSYT 15. Optionally, signalised junctions can be evaluated in Lane Simulation mode, which provides further capability such as intermittent stages and linked junctions. Lane Simulation mode also allows the evaluation of partially signalised roundabouts and the modelling of circulating lanes at roundabouts.
In Lane Simulation mode, ARCADY, PICADY and OSCADY junctions can be connected together.
Blocking back and basic interaction between junctions is handled. This capability can be used to model junction layouts that were previously difficult to model, or to model small networks of ARCADY, PICADY and OSCADY components.
Queues, delays and other results are calculated for each lane individually, and combined to give arm results.
Explicitly modelling with lanes means that it is often intuitively easier to see where or why problems occur.
