TRL Software > Products > Junction & Signal Design

Junction & Signal Design

TRL’s traffic design software packages are some of the most popular and widely used in the world, being used in over 110 countries for a wide variety of assessment and modelling work.

ARCADY is used for the assessment of roundabouts. It is able to accurately predict accident rates, capacity, queue and delay (both queueing and geometric) for almost any size of roundabout, ranging from multi-armed grade separated roundabouts to mini-roundabouts in suburban locations.

PICADY  incorporates TRL's extensive research into junction design issues and predicts accident rates, capacities, queue lengths and delays (both queueing and geometric) at non-signalised major/minor priority junctions.

OSCADY provides evaluation and optimisation of simple isolated signalised junctions. If combined with an ARCADY roundabout in Lane Simulation mode, it can also be used to evaluate partially signalised roundabouts.

ARCADY, PICADY & OSCADY are components of the modular Junctions package for designing and modelling priority junctions such as roundabouts and crossroads. All three modules are available and licensed separately or can be purchased as a complete package at a discounted rate.  


TRANSYT determines optimum, co-ordinated traffic signal timings and is suitable for urban intersections and networks, signalised or unsignalled roundabouts and motorway intersections. Its use around the world reflects its international applicability and the latest version builds on existing ability; TRANSYT is no longer just a network tool. Users can also optimise fixed signal timings in existing microsimulation models using the TRANSYT-VISSIM LINK and the TRANSYT-Aimsun LINK.