This paper describes COFIROUTE's two projects in the Ile de France, which use the concept of the driven urban tunnel, with small cross-section, for toll-paying light vehicles only. This allows two one-way decks to be constructed, one above the other, in one tunnel, so that construction costs are halved. In the completion of the A86 west loop on the second ring road around Paris, a tunnel is required for environmental reasons. In the other project, about 15 km of the congested south part of the Paris Ring Road is being doubled by building new lanes under the original road, as it is not practicable to widen it. In each project, there is a circular tunnel of 10m diameter, which can take three traffic lanes each way in a space 2.5m high; access is restricted to vehicles less than 2m high. A French Government Safety Commission decided that the tunnel was feasible, and would be very safe. Continuous and accurate real-time information is required on traffic at all points in real time. Each project has a control centre, which collects all data on traffic in the tunnel and on surrounding surface roads. Provision is made for efficient emergency services action in the event of accidents. Tolls are levied at the tunnel entrance.
Abstract