Page 38 - GCN, August/September 2017

Q&A CONNECTED VEHICLES
point. An adaptive traffic signal is one example, but you can also use it to figure out traffic flow.
Right now, we’re not at the point where we’re controlling the signals [in Ann Arbor], but we have a lot of information about the traffic flow and speed of the intersections.
What insight do you get from this?
First, it gives us information on the current state and when and where problems are. We all know
that signal phasing should be different for rush hour and non-rush hour. But most of the traffic signals are not programmed optimally. Teams are sent out to measure traffic on one day, and that becomes a “normal” day.
Cameras can add a layer
of adaptability, but they’re
still not as accurate as DSRC.
With DSRC, you can hear the
vehicle position and velocity
very accurately. You could use this information to build an adaptive model to react to the current conditions rather than the calibrated condition.
Tell me more about the adaptive signals in Ann Arbor.
Unfortunately, we’re not providing real- time adjustments yet. It certainly is the main concern in any city to do no harm. So the city is being very conservative. Officials want us to show more proof that this will do no harm and, better yet, improve conditions. We have done a lot of simulations that show adaptive signaling would make a significant improvement, but we probably have more convincing to do.
How significant is “significant improvement”? Even when we do the simulation, it
is a forecast. It’s not deterministic. Sometimes it shows an improvement of about 2 percent; other times it is as high as 20 percent.
What data are you collecting with the roadside units? Basically, the most important things are position, velocity and direction of vehicles. Those can provide us with speed, flow and queue length at every intersection.
transit projects. How do those projects relate to connected-vehicle and DSRC technologies?
The most critical things for the future of smart cities and the internet-of-things projects are data sources and what you can do — in other words, sensors and actuators. The more sensors I have,
the more information I have, the more I know the true picture of anything
— urban dynamics, transportation, anything people try to understand.
38 GCN AUGUST/SEPTEMBER 2017 • GCN.COM
How much of the data
are you collecting? Is it something that a typical DOT can handle?
It depends on your purpose. Let’s say I’m New York City, and I want to know the traffic dynamics and I want to collect year-round, then I would save everything.
However, in the real world, you wouldn’t save the data that much. Really, what happened yesterday is history. You save data only for the purpose of research. That’s its only long-term value.
But again, if I’m trying to understand traffic in winter versus summer, or how a festival or baseball game affects traffic, then I might save some data for benchmarking and research.
Many cities are launching smart-city and smart-
leverage
The No. 1 challenge to understanding those things is inadequate data sources.
No. 2 would be: What
can you do with the sensor data? Right now, you can call someone on the phone and they’ll do something for you. In the future, it would be nice to be able to directly access the actuators.
The people investing in smart city and infrastructure are adding to sensors and actuators, so certainly we will everything.
Are there any specific applications for DSRC in smart-city projects?
I think it is important to remember that government focuses on safety as the justification for requiring such a communication device. Safety is the No. 1 priority.
One possibility: DSRC can be viewed as an electronic license plate. So today we use a license plate, tomorrow we can use DSRC, and we no longer need a metal plate. The electronic license plate can also be used for electronic toll collection. Right now, toll collection
is very fragmented because states and cities have their own systems, but it is reasonable to expect DSRC to provide an ID for the car that can be used to control parking, toll collection and other things. •