Road tunnel operators are increasingly aiming to adopt a sustainable approach to road tunnel operation whenever possible. They are thus starting to look into ways of optimising the lifecycle performance of systems and equipment, whilst at the same time guaranteeing the required level of safety. One possible means of achieving this is based on monitoring the Reliability, Availability, Maintainability and Safety (RAMS) of systems/equipment, based on pre-defined requirements (these aspects are clearly outlined in PIARC technical report 2017R02EN: Road tunnel operations: first steps towards a sustainable approach).

It can be argued that the RAMS methodology is directly linked to all three pillars of sustainable tunnel operation (economic, social and environment). By guaranteeing the reliability and availability of individual tunnel systems/items of equipment, particularly when they are of a critical nature in terms of safety, the tunnel as a whole can remain open to users. For all tunnels, whether in an urban or non-urban environment, the societal and economic impacts of a tunnel closure, even for a short period, are evident.

The maintainability of systems contributes largely to their lifecycle performance, reducing not only renewal costs but the environmental impact that such equipment renewal can have.

The RAMS methodology has been extensively used in many industries. In the transport sector, it was first used in the railway industry, where a RAMS standard (EN 50126) has been developed. This standard can be adapted to road transport, including road tunnels, and is thus gaining increasing interest from both private and public road tunnel operators.

The aim of this report is to provide an initial introduction to the RAMS concept. It first explains why and when the concept should be applied within the context of road tunnel operation and then goes on to describe how the concept can be applied by using the standard EN 50126 as a basis.

The report also gives an overview of existing RAMS-based standards/guidelines around the world and provides the results of an international survey conducted by the working group on how road tunnel operators currently take into account reliability, availability, maintainability and safety aspects in their respective countries.

Readers are advised that this report should not be considered as a manual for applying standard EN 50126 to road tunnels. The report is not intended to be used as a standalone document and to make full and efficient use of its contents, readers should acquire additional literature, notably the above-mentioned standard.