Experience shows that a kilometre in a tunnel is always more costly than a kilometre of the same road outside. Underground structures require systems and equipment that ensure safe operation under normal operating conditions and allow the protection and the evacuation of users and the intervention of rescue services in case of an incident, accident or fire. These facilities not only involve considerable investment costs but also result in particularly high costs for operation and maintenance. Thereby the role of the operator is to ensure the continuity and the safety of operation in a context of controlled costs.
In all cases, even a high standard of tunnel operation may not allow an optimisation of operational costs, if the design and the construction of the tunnel have been undertaken to a low quality level. Operational costs therefore need to be a major consideration during the different phases of the project and the work execution. Solutions need to be found well before becoming an issue during the operational phase.
Operational activities have to be organised at an adequate level in order to ensure that the expected lifecycle of the equipment is met, without compromising mandatory operational performance requirements. The lifecycle of equipment in tunnels is normally shorter than in other environments, since the atmosphere in tunnels is particularly corrosive.
The Technical Report 05.06.B "Road Tunnels: reduction of Operating Costs" is entirely devoted to operating costs and in particular focuses on how to reduce them.