This paragraph provides general recommendations to those who intend to pay particular attention to human factors when designing a new tunnel or refurbishing an existing one. Its objective is not to sum up the fundamental technical recommendations developed in the PIARC reports regarding inclusion of the human factors when considering safety. It aims above all at summing up the main methodological recommendations to be implemented when it is desired to pay particular attention to these aspects.
Three main points deserve to be underlined from this viewpoint:
The first point particularly concerns the design of new tunnels for which it is fundamental to intervene as far upstream as possible during the studies. This should allow better account to be taken of the main factors which govern the behaviour of users in road tunnels. Among these main factors, the following can be notably mentioned:
The second point concerns consideration of the work carried out in the field of integration of human and organisational factors with respect to safety, notably aiming to make best use of knowledge accumulated to date in the field of general road safety, and evacuation in crisis situations in particular. This can take shape in two ways: either by referring to general lessons learnt from work carried out in this field (PIARC recommendations for example), or by involving human science specialists (psychologists, experts) in the project. The advisability of involving human science specialists deserves to be considered both for the design of new tunnels and for the refurbishing of existing ones. Obviously it applies only for the most important projects with particular issues (cross-border and/or particularly long tunnels, tunnels of limited dimensions, etc.)
In this field and as is already the case for open-air infrastructures, it is necessary to remain very prudent before implementing a technical solution which appears at first sight to be satisfactory. The lessons learnt from real events or from the numerous exercises held in tunnels do indeed show that the technical choices made by engineers specialised in the fields of equipment and safety in tunnels are not always the most appropriate from the viewpoint of user behaviour.
Independently of the possible implication of human science specialists, it is obviously necessary to take care to ensure a wide consultation of all the actors concerned at all times. In particular, the intervention services must be closely associated with the design of the safety equipment (particular attention must be given to features provided for self-help for evacuation of users).
The third recommendation concerns the tests and trials necessary to validate innovative choices when the latter prove to be desirable. Much has already been learnt in terms of taking human behaviour in tunnels into account. Designers are invited to pay attention to these factors when finalising all the safety measures in tunnels. When it proves to be necessary to develop innovative means, the preliminary test phases must not be neglected (indoor testing for example), nor trials on site. These trials could be usefully performed with support from experts in the field of human sciences. Their objective will be to validate the innovative measures proposed before deployment in tunnels.
As a conclusion and in general, we cannot but recall the need to show much pragmatism and humility in this field. A basic principle consists in preferring simple and intuitive solutions whenever possible, in line with what is currently in practice in non-confined conditions. These types of approach guarantee that the measures implemented are liable to be well understood and adopted by the users.