| Weather Responsive Intersections
business development and marketing
for PTV’s traffic department. “You
can model the urban environment
and run simulations analyzing the
factors you are interested in, whether
it’s average speeds, emission levels or
waiting times.”
Fu’s team’s computer modeling
involved adjusting the timing of
signals at a single intersection and on
a stretch of road with four
coordinated intersections. Taking into account coordination
between networked signals was
a “critical” consideration says Fu
because “one of the key parameters
in network coordination is
the travel time between the
intersections, which can actually
change significantly under poor
weather conditions.”
“So it was important to offset the
signal timing to ensure that the
coordination was maintained,” he says.
By doing this Fu’s team were able
to demonstrate a reduction in delays
for the coordinated intersections of
up to 20%, even though the amber
light interval was extended to allow
for longer stopping times.
Real-world deployment
With the results in, the question then
becomes how to apply Fu’s research
in the real world. Before answering
this question, he says, it’s important
to understand current technologies
for signal timing solutions.
The most common is known as a
fixed time plan (FTP) system, he says.
This is usually used for traffic signals
that are not networked and where the
traffic pattern doesn’t change a lot
over time. In a FTP system the signal
timings automatically switch
between different schedules – peak
and off-peak, for example – according
One of the key parameters in
network coordination is the travel
time between the intersections, which
can actually change significantly under
poor weather conditions
Liping Fu, director, Innovative Transportation System
Solutions Lab, Waterloo University, Ontario
PHOTOGRAPHS: LADYSUZI, ICEPHOTOGRAPHY, TIBOR13, MNSTUDIO/STOCK.ADOBE.COM
Above: Traffic slows
during snowstorms,
but new SPaT
programming can
keep if flowing
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November/December 2019 Traffic Technology International
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