Signs indicating the emergency escape routes in tunnels are of critical importance to the safety of tunnel users, given the particular hazards of fire and smoke within tunnel environments. Sadly, the government’s irrational position on units of measure even extends to these safety critical signs, as illustrated by the different units being used by the same authority on adjacent tunnels.
By international agreement under the auspices of the United Nations, new road signs showing pedestrian escape routes with distances were adopted for international use in tunnels in 2003, providing a common design for use in all countries to improve evacuation in the event of a tunnel incident. These new signs added the distance in metres to the nearest exit, as illustrated in the updated Vienna Convention on Road Signs and Signals:
In the UK, the Department for Transport (DfT) noted this advance, but decided that new signs using obsolete imperial units should be erected in tunnels across the UK, regardless of whether young people or visitors to this country may need to be evacuated from a tunnel, and heedless of government guidance that metric units are the primary system of units in the UK.
New signs are being installed by highway authorities in tunnels across the UK, including in London, where Transport for London (TfL) are refurbishing road tunnels with new signs showing the distance only in yards (and to the nearest yard!), as shown in this picture taken in the Rotherhithe Tunnel:
Meanwhile, TfL re-opened the refurbished East London line last month, whose tunnels pass below the Rotherhithe road tunnel.
This being the UK, the same standards do not apply in road and rail tunnels. New escape signs have also been installed by TfL within the rail tunnel adjoining the road tunnel:
Unlike the road tunnel, the rail tunnel is signed in metres, meaning any visitors are able to judge the distance to the emergency escape. Full marks to the rail authorities for using units all potential users will understand, but it highlights the mess that the UK is in when adjacent tunnels, one road and one rail, under control of the same authority, provide critical passenger safety information in different units and expect users to be able to understand both.
Sadly, other backward steps have been made within the rail tunnel. Line distances on the London Underground network changed to kilometres as long ago as 1972, but with the conversion of the East London line to National Rail standards, new mile and chain marker posts have replaced the metric signs which have stood for nearly 40 years. The new yellow sign below indicates the 3 ¾ mile mark:
At least these signs are not for public consumption!