TO FIND oneself in an emergency situation, having to evacuate from an unfamiliar building, or environment, is stressful enough for any able-bodied person, but when suffering from reduced mobility, that sense of foreboding is greatly accentuated.

When an evacuation involves a potentially smoke-filled tunnel and you have difficulty walking, seeing or perhaps even hearing, it adds a whole new dimension to the situation. Indeed, even without those concerns, many people find travel through a tunnel an already unpleasant and unnerving experience.

The World Health Organisation calculates that at least 15 per cent of the world’s population have some form of physical disability or other impairment. That percentage equates to over a billion people, with 80 per cent of them living in developing countries. In the UK alone, there are 11 million people registered as "Disabled", 4.6 million of whom have walking difficulties with 800,000 wheelchair users. There are also half a million "Motability" adapted vehicles on UK roads.

However, the term "reduced mobility" embraces many more individuals and groups who might experience difficulty in evacuating a tunnel to a place of safety during an emergency. Approximately 20 per cent of the population in the European Union (EU) is over 60 and many find walking any distance, or climbing stairs, extremely arduous due to degenerative diseases like arthritis, osteoporosis, heart, lung, knee and hip problems.

Equally, one could make a reduced mobility argument for the morbidly obese, a pregnant woman, or a young mother travelling alone with two or three small infants. Her walking speed to reach a place of safety would be determined by the pace of the slowest infant or the degree of difficulty with which she could carry the youngest.

Add to that those who may be physically capable of selfrescue but become paralysed by fear and find themselves unable, or unwilling, to evacuate the perceived "safety" of their vehicle plus those who suffer from severe visual or hearing impairment, and it is conceivable that one in every six persons involved in an incident requiring evacuation might find difficulty self-rescuing to a place of safety if they have to climb up onto an elevated walkway, use a staircase, or walk up to 250m, perhaps on a steep gradient, to reach an exit.

In 1995 the UK, through the Disabilities Discriminations Act (DDA), made it unlawful to discriminate against people in respect of their disabilities in relation to employment, the provision of goods and services, education and transport. In general, UK designers have made efforts to comply within reason, however that is not always the case elsewhere.

When the DDA was replaced by the Equality Act in 2010, the type and scale of any ‘reasonable adjustments’ a service provider was required to make to ensure people with disabilities could overcome "any substantial disadvantage" posed by the service providers operation was far more prescriptive, with mention of ramps, stairway lifts, wider and automated doors together with better lighting and clearer signage.

In tandem with UK legislation, the United Nations (UN) published a Convention on the Rights of Persons with Disabilities, which all members signed up to in 2006. It called for reasonable accommodation by modifying existing infrastructure without imposing a disproportionate cost, for the first time alluding to the notion that disability provision should be considered when designing "new infrastructure". The wording of two articles has particular relevance for tunnel designers and operators, whether for road or rail usage.

UN Article 9 – Accessibility

"Access on an equal basis to the physical environment, of transportation by the elimination of obstacles and barriers to accessibility, these to include buildings, roads, public transport, and other indoor and outdoor facilities."

UN Article 11 – situations of risk and humanitarian emergencies

"All necessary measures shall be taken to ensure the protection of persons with disabilities in situations of risk."

Furthermore, the EU Charter of Fundamental Rights outlaws discrimination on the basis of disability with the EU Directive 2004/54/EC on Road Tunnels stating that, "the needs of the disabled should receive particular consideration during all design processes", stopping short of specifying "step free" escape routes.

Eminent investigative psychologist Professor David Canter maintains that the common notion of panic during emergency situations is not strictly true and that most fire evacuations are actually quite orderly, noting that in crisis situations one or more leaders often emerge from the affected group to help the young, old and infirm, reach an exit – often putting themselves at risk. A tunnel designer or operator however cannot, and should not, rely upon that possibility as part of their planning process.

So what are the particular issues that might affect those with reduced mobility in the event of a tunnel-related emergency?

¦ Currently, there is no universally accepted form of identification for a private car or adapted van carrying a disabled person, nor means to signal they are in distress.

¦ Vehicles adapted for use with a chair lift need at least three metres clearance to the rear to permit egress. Those driving adapted vehicles need to be able to open the passenger door fully to open their folding chair and transfer into it.

¦ Clear passage towards an exit on a congested roadway may not be possible for someone in a wheelchair. Additionally, there is an increased risk of the infirm being pushed over or brushed aside by persons to the rear moving at a quicker pace.

¦ S.O.S telephones at emergency points/niches are generally fixed too high or beyond reach for wheelchair access.

¦ A raised kerb, elevated walkway transition, and/or a pedestrian impact guardrail presents a considerable, and sometimes insurmountable, barrier at an entrance lobby to a fire exit door.

¦ Raised concrete walkways up to 1.5m high which lead to exit doors, can only be accessed via climbing steps at periodic intervals. In previous emergency exercises it has been noted those with mobility difficulties pass by elevated cross tube escape doors in the belief they could reach the tunnel portal instead.

¦ Emergency exits at up to 500m spacing, as specified in European Directive 2004/54/EC, are too far apart for a person of reduced mobility, moving at around 0.5m per second, to reach a place of safety, unaided, before being affected by uncontrolled smoke. In the UK however most escape doors are spaced at 100m as per BD78/99.

¦ Stainless steel exit doors, particularly the self-closing sliding type, are either too heavy, or awkward, to open without assistance.

¦ Although most escape routes feature emergency level battery protected lighting, general in-tunnel lighting levels are often insufficient for persons with impaired vision, especially when affected by smoke.

¦ Emergency signage is generally inappropriately sized, and in some cases, coloured, for persons with impaired vision. Text size has traditionally targeted those with what is perceived to be "average or normal" eyesight, with no allowance or reasonable adjustment for the partially sighted.

¦ In some countries, even where there is step free access from the road into a fire exit, onward passage to a pressurised safety refuge, or parallel escape gallery, is negotiable only by climbing stairs. Compliant ramps or lifts for wheelchairs are a rarity