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most efficient use of energy, at the least cost, and integrate” all
the elements of a complete system from different manufacturers.
In addition to integrating services, the company develops and
manufactures the core computer systems they deploy. They’re
working on a novel means of communicating with the public: in
Madrid, they’ve designed a system whereby riders can send a text
message with the bus number and stop identifier, and immediately
receive back a text with the arrival time of the approaching bus.
In an ideal world, traffic managers need to peer into the near and
distant future to evaluate traffic control options. How will a road
closing affect vehicle flow, and what are the best routes for redi-
recting cars and buses? When an event such as an accident occurs,
what are the best diversion plans to facilitate movement?
Tekia Ingenieros (Tekia), based in Madrid, has been tackling
the planning for traffic control in tunnels. The company’s most
ambitious project to date involved analyzing the safety needs of
the newly built tunnel section of one of Madrid’s ring roads; it
is buried under a river, and the tunnels stretch out for more than
30 miles (50 km), making it the world’s longest underground
automobile traffic str ucture.
Tekia engineers looked hard at potential safety threats to the
tunnel, such as heavy traffic, or accidents, fires, or explosions.
They brought together a roundtable of security experts for a
year. Using all the expert information and possible scenarios
gleaned as part of their program, and aiming for the best out-
comes for each scenario, Tekia then built an expert operating
system to help a city planner decide in real time which solutions
would best solve problems that arise.
Such traffic modeling software is the specialty of Trans-
portation Simulations Systems (TSS), a Barcelona-based traffic
modeling company offering more than 25 years of experience
helping cities plan for traffic flow.
TSS developed its modeling program, Aimsun, using research
performed at a Barcelona university. At the time, in the 1980s, com-
pany founders realized that the big-picture regional models that
were being used for strategic planning might be able to predict pop-
ulation and traffic growth on a large scale, but were not much help
in determining the best solutions for small-scale changes in traffic.
Company engineers wanted to create a model that could
examine behavior on the micro level. “What will happen if
there’s road work on a major arterial that also has a tramway
and lots of traffic? You can experiment with adjustments to
make the situation more tolerable—maybe change the light set-
tings, restrict access to some roads, or send the police out to
direct traffic,” says Alex Gerodimos, TSS commercial director.
Despite the much lower computing power available at the time,
TSS’s new models were able to accurately predict the results of
interventions on this more modest scale.
But while this was helpful for planning, these models could
not yet assist real-time traffic management. Since then, leaps in
computer processing speeds, coupled with the greater quantity
of real-time information now available on the details of traffic
flow, have allowed a revolution in modeling: TSS and its part-
ners have developed both small- and larger-scale Aimsun mod-
els that can be used by city traffic managers to determine the
consequences of changes to traffic in real time, allowing them
to make rapid decisions based on predictions from the models.
For instance, an ambulance might need to reach the scene
of an accident, but that accident has already caused changes
in traffic that are rippling outward. The models can provide
images of the possible ambulance routes and suggest which
will be the fastest.
In Madrid’s municipal traffic control center, the graphic simu-
lations hover on a screen, allowing the controller to visualize
the consequences of particular choices 10 to 20 times faster
than they would occur in the real world. The Aimsun software
used here is used to model traffic for other cities in 60 coun-
tries, including the entire nation of Singapore.
Telvent uses a modeling program for its control systems, and
has been able to incorporate weather and pavement conditions
into the traffic management systems for cities such as Alberta,
Canada. “We can use weather information for precise support.
For instance, we can predict what the pavement conditions will
be over the coming hours,” says Cáceres.
sMarT inforMaTion for
Drivers today can take a quick glance at a number of web pages that
claim to show current traffic conditions. “We believe this informa-
tion is inferior—or in some cases useless,” points out Gerodimos.
“It’s often based on what we know now.” But if the information is
not available, because a particular road isn’t monitored for traffic, it
appears traffic-free, no matter what the actual conditions. A model
can solve that issue, he explains, by extrapolating for the entire city.
And the second problem, he says, is that the driver hasn’t left
the house yet, and traffic may change rapidly. Gerodimos envi-
sions a future in which predictive models will be available not
just to traffic control managers, but to consumers as well. With
software such as Aimsun running, the car’s GPS system could
not only offer current traffic conditions, but recommend the
best course for a 30-minute drive based on future traffic patterns.
“If we provide consumers with smart information about
options for mobility, we’ll improve both mobility and the effi-
ciency of the infrastructure,” explains Telvent’s Cáceres.
Supplying easily accessed information is the goal of the system
designed by Telvent for New York City, San Diego, and Tennes-
see. It relays real-time information on traffic and public trans-
portation via the Internet. Citizens can also dial 511 to listen to
up-to-the-minute responses provided by a computer-generated
interactive voice response system.
Today, many consumers receive information about traffic
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