TRL: Junctions 8 Roundabout Module
The world's leading software for the assessment of roundabout capacity, delay and accident risk.
NOTE: Junctions 8 Roundabout Module now links dynamically to AutoTrack Junctions.
ARCADY (Assessment of Roundabout Capacity and Delay) has been developed over the last 30 years by TRL and is used for predicting capacities, queues, delays (both queueing and geometric) and accident risk at roundabouts. ARCADY is an easy-to-use and helpful tool to aid the busy traffic engineer in designing new roundabouts as well as assessing the effects of modifying existing designs.
At its core, ARCADY uses the well-established TRL/Kimber capacity relationships, which take into account key roundabout geometries such as entry width, flare length and inscribed circle diameter. This empirical framework intrinsically links roundabout geometry to driver behaviour and in turn to predicted capacities, queues and delays.
ARCADY has been successfully used to design and re-design thousands of roundabouts throughout the world. It has a host of satisfied customers including governments, multi-national organisations and universities. Its easy to use and intuitive user interface mean that it can also be used effectively by small consultancy companies. It can model both drive-on-the-left and drive-on-the-right roundabout systems, making it applicable to junctions in many countries. Level of Service and Peak Hour Factor outputs are available.
Read Mike Hutt's paper Roundabout Geometric Modelling which outlines how ARCADY came to be the most widely accepted vehicle capacity analysis system.