THICK SMOKE prevented motorists from finding their way to emergency exits in the minutes after fire broke out in Switzerland's St Gotthard tunnel.
This was despite signs being clearly marked with indicator lights at 35m intervals.
One lorry driver who escaped the blaze said could not see the way to the nearest fire exit because of the thick choking smoke that filled the tunnel.
Instead he dropped down as low as he could and felt his way along the tunnel wall.
Many drivers ignored regulations, turned their vehicles around and drove out of the tunnel, but officials said that while escape procedures worked effectively, this action cost some drivers their lives.
Officials were quick to point out that the safety systems in place worked well. They cited the escape of a driver directly behind the lorry that crashed as evidence that even those caught up in an accident could escape.
It seems that most of the lorry drivers with experience of driving through long Alpine tunnels made an escape.
Drivers and passengers in cars appeared to account for most of the death toll. Some are said to have been overcome by fumes as they tried to turn their vehicles around.
The tunnel is fitted with video cameras and smoke detectors.
As soon as fire broke out, officials turned the tunnel entrance lights to red to stop vehicles entering.
But the 11 deaths in a tunnel previously regarded as safe has led to a massive rethink of tunnel safety across the region.
A tunnel spokesman said that regular drills were carried out by the fire brigade and police but that they were still surprised at the intensity of the fire and length of time it burnt.