Traffic Management |
From 2020, Stefan Hollesch,
portfolio manager of
Hamburg Traffic Systems
says the plans to add wi-fi
tracking technology to the city’s
network. While the thermal
sensors provide data from one
specific point on an intersection,
the inclusion of wi-fi tracking
will provide data about what is
happening between different
installation points. It monitors
the wi-fi mac addresses of
devices such as smartphones,
making it possible to determine
travel and route times along
road segments. The wi-fi
signal strength information
determines the relative
proximity of vehicles allowing
it to measure delay times at
intersections.
“We’ll be able to calculate the
live travel times between two
points, which will be even more
useful for anyone accessing the
data,” says Hollesch.
Making data richer
Hamburg traffic mangers plan to add wi-fi detectors to the network to
augment the data being gathered using thermal imaging
before in Europe. Until recently, the
high cost of thermal cameras would
have prohibited purchasing so many
of them, but prices are dropping and
the technology has improved. Stefan
Hollesch says the main reason they
were chosen by Hamburg was
because they perform better in poor
visibility, especially in bad weather
or during the nighttime. Being able to
rely on the cameras in all conditions
means Hamburg is able to monitor
intersections closely 24 hours
a day in all conditions.
Hollesch’s assertions about
thermal cameras were confirmed
by academic research from engineers
at McGill University and the
Polytechnique Montréal in a 2016
paper Traffic data Collection Using
Thermal Cameras under Varying
Lighting and Temperature Conditions.
The researchers compared the
performance of regular visible-light
cameras with a resolution of 1920 x
1080 pixels with thermal-video
sensors with a resolution of 368 x 296
pixels. The thermal cameras used in
the research were manufactured by
the Oregon-based company FLIR,
which also provided the cameras
for Hamburg.
With shadows or at night, the
performance of the regular
camera was greatly reduced, and the
thermal camera was superior in terms
of detection, classification, and vehicle
speed measurement
Traffic Data Collection Using Thermal Cameras under Varying
Lighting and Temperature Conditions (2016)
The researchers concluded that the
regular camera only narrowly
outperformed the thermal camera in
terms of detection and classification
of all road users during daytime
conditions, but at nighttime the
thermal camera came into its own
and was far superior, especially
when it came to the detection of
pedestrians and cyclists.
The research states: “Regular
video works well for ‘overcast’ and
‘sun, little shadow’ conditions
without lighting interference, such as
shadow, glare, low visibility, or
reflection. The thermal camera
performs similarly in these
conditions…. However, with shadows
or at night, the performance of the
regular camera was greatly reduced,
and the thermal camera was superior
in terms of detection, classification,
and vehicle speed measurement.”
In the final analysis, the paper
asserted that a thermal camera’s
insensitivity to lighting interference
solved issues associated with
using cameras for traffic data
collection. The thermal cameras
proved to be “more reliable and
stable” in round-the-clock data
collection, they said.
Privacy protected
Another important point in
the research was that
thermal cameras
presented no privacy
issues, which are
a major hurdle for videobased
sensors, especially
in the US and Europe.
“There aren’t the same
privacy issues because
although our cameras give
enough detail to know the
723,000
The number of jams
recorded in Germany’s
Bundesrepublik in 2017, up
from 189,000 in 2011
Below: One of the
thermal imaging
cameras installed on
a traffic signal post
in Hamburg
034 Traffic Technology International November/December 2019
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