Managing incidents on motorway networks : some developments and field results in Scotland.

The network structure of roads and motorways offers the opportunity of improved incident management. The possibility of diverting drivers to new routes by-passing the links where traffic congestion exists enables network operators to minimise the total time spent in the road system by making better use of available capacities of the network. Developments in this field have been made for over four years within several French and European cooperative projects. The purpose of this paper is to describe the operational version and give the evaluation results of the OPERA aid-to-decision system which was developed and tested in the QUO VADIS project and was finalized and implemented within the TABASCO project since March '97. The OPERA system was developed as an on-line prototype within QUO VADIS and it has been enhanced and extended to manage a wider network and a greater number of VMSs (15 currently) within TABASCO, as part of NADICS (the National Driver Information and Control System). NADICS draws together under one control system the existing driver information and traffic control systems which operate on the strategic network, within the Glasgow conurbation, around the Forth Estuary and on the western approaches to Edinburgh.