:D Optical Signaling Systems
Optical signaling systems – what a kind of bureaucratic language! Everybody
is calling this „traffic light“. Originally a traffic light was a kind of
pending light in the middle of an intersection. This is still the case in
some countries, but in Germany this almost completely ceased to exist.
Now let's talk about traffic lights in Düsseldorf. Düsseldorf has 620 traffic
lights, connected to a traffic computer network, either via cable or via
mobile network (GSM). Times where you could see large gray switchboards on
every crossroad, full of process control computers, assembly groups, cables
and wires are long gone. Meanwhile all traffic lights have been vamped up and
because of various detectors, they are theoretically able to operate
dependending on the actual traffic.
However, usually they are operating based on the time of day, following a
special plan with morning peak, evening peak and if necessary night shutdown.
This plan could be influenced by pedestrians, trams or buses which can request
additional green lights.
Traffic management is quite a complex matter which depends on geographic
conditions (traffic flows along with connections, separations, or crossings),
or politically motivated decisions like prioritization and acceleration of
public transport. The common goal is a streaming traffic flow, also known as
phased traffic lights (in German: “green wave”).
Those nicely looking little men for pedestrians from former German Democratic
Republic (GDR) do not exist in Düsseldorf, altough some of these imports from
East Germany have been recognized in some cities in Western Germany. But
Düsseldorf has another unique feature:
Yellow lights for pedestrians!
Let's come to the mystery now. This is a small Google Earth lookup task:
Find this place
If you are not able to find the solution – in case of emergency, you could
visit a callbox at the Luegplatz in Oberkassel and get help.
There is no geocache to find at the listed coordinates. No
cache which is part of the :D series requires to trespass
rail tracks or highways. Caches located on private property
have been placed there with explicit permit of the owner.
If a riddle requires visiting third party websites or
downloading additional files, we guarantee that at the time
of publish, they don't contain any virus or harmful