Tuesday, May 10, 2011

Digitalized Tunnels are Safer

Creative Commons photo by Peter Fiskerstrand.

The government in Norway has decided that FM will be switched off in 2017. But what does that mean for the radio coverage in road tunnels? Norway has over 1,200 tunnels, 500 of which are longer than 500 meters.

180 of those tunnels do currently have FM coverage for NRK P1, some also carry P4, the biggest commercial radio station. 30 tunnels do currently have DAB coverage. By 2017 the 180 tunnels now covered by FM will need to be covered by DAB. The Norwegian Road Authority does however have a bigger goal in mind. By 2020, all the 500 tunnels of more than 500 meters in length will be covered by DAB/DAB+ and possibly also by DMB.

Why is The Road Authority so keen on DAB? Because DAB doubles as an emergency system. In case of a car crash, accident, fire or similar the operator who follows the tunnels through video cameras will override all radio stations inside the tunnel and read out potentially life saving instructions to drivers and passengers. If the receivers also have a screen, additional info such as maps showing the nearest exit or the the nearest emergency phone can be shown.

Where is this stated? The Norwegian Road Authority has published a manual on Road Tunnels, Manual 021E. The English version was published in 2004. There is a revised version from 2010 with some minor updates, although this version is only available in Norwegian. The manual is very detailed and is considered so well written that it is also being used by several American states for road tunnels and by the Norwegian Railroad Authority for railway tunnels.

The relevant chapters are 602.3 Radio equipment, 602.31 Communication equipment and 602.32 Broadcasting equipment with "interruption facilities." The regulations stated in such an official manual have been made are part of the law and must be fulfilled.

That means that Norway's many long tunnels will be safer than before. The emergency system does however require that the radio (or DMB player) is actually turned on with the volume on (it cannot turn the radio on for you). Information encouraging drivers to keep their receivers on should therefore ideally be posted outside all long tunnels. It is not known if such road signs will be put up.

The Norwegian Road Authority is required by the EU (even though Norway's not a member) to have such an emergency system in place, but The Norwegian Road Authority has imposed tougher rules on themselves than what is being required. The EU directive calls for such emergency system in tunnels above 1,000 meters of length, not 500. Norway does, in other words, not only do what the EU requires them to, but even more for the sake of safety.

The EU directive?
of 29 April 2004
on minimum safety requirements for tunnels in the
Trans-European Road Network.

Chapter 2.16 deals directly with what has been covered here:

2.16. Communication systems
2.16.1. Radio re-broadcasting equipment for emergency service use shall be installed in all tunnels
longer than 1 000 m with a traffic volume higher than 2 000 vehicles per lane.
2.16.2. Where there is a control centre, it must be possible to interrupt radio re-broadcasting of
channels intended for tunnel users, if available, in order to give emergency messages.