ENVIRONMENTAL AND TRAFFIC CONTROL SYSTEMS IN ROAD TUNNELS. SINO-BRITISH HIGHWAYS AND URBAN TRAFFIC CONFERENCE. PAPERS PRESENTED AT THE CONFERENCE HELD IN BEIJING 17TH-22ND NOVEMBER 1986

In a road tunnel, special consideration must be given to control of the environment within the tunnel and traffic using the tunnel. This paper discusses in general terms the factors to be considered and the solutions that can be adopted for lighting and ventilation within a tunnel, together with appropriate traffic control. During daytime, the level of lighting should be sufficient to allow the eyes of the drivers to adapt appropriately; during night, a lower level of lighting is needed inside the tunnel, but both entry and exit approach roads should also be lit. Ventilation is needed to ensure that the air inside the tunnel is unpolluted, especially by carbon monoxide, and that visibility remains good. Adequate traffic monitoring and control are especially important, both in the tunnel and on its exit roads. Any incident should be avoided, which could result in drivers being stopped in the tunnel for long periods, since it can lead to confusion and panic and cause difficulties of access for breakdown and emergency teams. Other systems of comparable importance in tunnels are communication systems (including emergency telephones, internal and external telephones, radio, and public address systems), fire detection and fire fighting systems, and power supplies. (TRRL)