The programs ARCADY and PICADY, which are for the calculations of delays and vehicle queues at roundabouts and priority junctions, respectively, have now become well-established computer-aids for traffic engineers. The programs, and the techniques behind them, were developed at the transport and road research laboratory, and subsequently distributed and maintained by the hcd sections of the UK department of transport. this report describes the development of a second generation of these programs. The modelling changes have centred on:- allowing a wider range of priority junction types, such as four-arm junctions (with or without staggered crossing movements), flared minor road approaches, and calculating delays caused by major road right-turning traffic; - allowing traffic demand to be defined in several ways, such as by turning movements or by link counts; - including effects of adjacent pedestrian zebra crossings; - allowing site-specific observations to be included in the calculations. The computing changes have been concerned with developing versions that will run on a full range of computers from microcomputers to mainframes. The programs are also available in either batch or interactive versions. The batch versions allow an easier method of data input to be used, while the interactive versions assist the user with inputing and editing of data, as well as supplying the user with summary information on the terminal screen about the changing state of the junction during the modelled period. (a) for the covering abstract of the seminar see IRRD 273510.
Abstract