need a camera every 100m,” Hegedus
explains. “It depends on curvature,
because your line-of-sight is better in
a very straight tunnel and, if you
choose high-definition cameras, then
you need fewer. That’s the maths we
are always doing.”
Fire-detection technology
Risks to life are magnified in a tunnel,
especially where fire is involved,
making swift and reliable detection
and response central to safety. “First,
you have smart cameras with smart
software, trained to recognize a
vehicle on fire,” Hegedus continues.
“The system alerts the operator,
automatically switching to the correct
screen to show them the case, and we
also have linear fire detection. These
| Tunnel Management
of scenarios are needed, which can be
manually initiated by a human
decision-maker. “But if a line to the
control center is severed, the tunnel
must be autonomous enough to close
and evacuate automatically,”
Hegedus adds. “It’s highly automated
because it has to be failsafe.”
Trafik Stockholm, the unified
control room for the entire Stockholm
A daily commute through
18km (11 miles) of
Stockholm Bypass tunnels
could take over 15 minutes, even
with top speeds of 80-100km/h
(49-62mph). This raises the
spectre of inattention, fatigue or
claustrophobia impairing driver
performance and imperilling
safety. One part of the solution
lies in design. “To make it
more engaging, you don’t just
have a straight tunnel,” says
Trafikverket project manager
for installations, Leif Eklöf.
“Something must happen to
make you focus on driving.”
In addition, the Stockholm
Bypass has an aesthetic design
pProgram based on a study of
how this complex traffic system
could affect human variables
such as visual distraction,
lateral deviation, speed
changes and braking behavior.
“Monotony is the main factor
we wanted to reduce through
aesthetic design,” explains
Dubliner Cian O’Reilly, project
manager for aesthetic design.
“We will install artworks at five
tunnel exits, chosen through
a competition for Stockholm
public artists. These concepts
echo the geography and culture
above each exit, particularly
connected with the Royal Palace
at Drottningholm, the suburbs
of Vällingby and the commercial
area at Kungens Kurva.”
Driver engagement will be
further enhanced by pathway
lighting constellations. “They’re
really thin strips of light,
strategically positioned on the
walls where the tunnel turns the
most, intended to lead the eye,”
says O’Reilly. Any oppressive
sense of subterranean
confinement will be alleviated
by air-exchange-station
lighting, which will provide a
visual metaphor connecting
drivers to the daylight realm
above. “It’s similar to sunlight
through blinds on a window,” he
continues. “It creates a sense
of natural light coming in where
we take in fresh air and extract
dirty air, which shifts during
dawn, dusk or night time.”
Attention!
Creative and colorful installations inside the tunnel ensure drivers
traveling underground for extended periods do so safely
Below, right and
above right: Beautiful
and dramatic art
installations in
the tunnel are
designed to help
to reduce driver
fatigue and enhance
concentration on the
road ahead
systems send a signal to the tunnel
control system, which goes into
evacuation mode. Ventilation is
turned on, lighting increased, public
address systems activated,
emergency exits highlighted and
the tunnel closed with barriers, to
prevent more vehicles entering.” For
multiple systems to work in concert,
preprogramed responses to a range
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July/August 2019 Traffic Technology International
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