SmartSensor Matrix's true presence detection at the stop bar has enabled Moab, Utah to implement a peer-to-peer adaptive system that addresses seasonal traffic needs at a fraction of the cost.
Matt Luker and Utah Department of Transportation
To tailor traffic signal timing to fluctuating traffic volumes by using an adaptive system in Moab. A peer to peer system that looks at whether or not cars are being detected during the green phase. It counts up every tenth of a second classifying the time as used or unused green time. The measured value is then compared to an ideal value. If there is more dead time on the detectors then expected then it is known that less green time was required during that cycle. If the detectors are occupied more than predicted than it is assumed more green time is required. Data from the last 3 cycles are averaged out and the next cycle will allow a more ideal green time and so forth adapting green time to what is necessary.
Problems and Challenges
Moab, Utah is a tourist destination which results in traffic patterns that can be unpredictable. With a variable mix of local, truck, and tourist traffic it was hard to predict the busy times. but past systems weren't necessarily a good fit.
In the past, they would schedule special timing plans on weekends when they expected heavy traffic, but they didn't always guess right.
Since Moab is in a remote area far enough away from the people who would operate the adaptive system with engineers in Salt Lake City and technicians in Richfield the solution needed to be easy to operate that could stand on its own without much intervention.
Luckily new advancements in the latest generation of signal controllers, such as the ones UDOT uses, allow for special programming to do what was previously impossible. So, Matt Luker developed programming for the system utilizing existing local controllers and detection. In addition, the peer-to-peer system does not require a server.
The new signal controllers allow custom programming to do features that aren’t built into the software of the sensors, they used the custom program to look at the volume of traffic on Moab’s main street.
SmartSensor Matrix was used for reliable detection.
In the last year the system has improved traffic flow on Main Street in Moab by increasing the amount of green time for those movements when traffic is there to use it. When traffic on Main Street dies down, the cycle length comes down to reduce delay for pedestrians and cross-street traffic.
This system benefited the town of Moab but cost only a little more than the cost of the standard controllers and detection that would be installed anyway. These kinds of adaptive systems typically require a server, communications network, a lot of programming, and special controllers. The Federal Highways Administration estimated that it can cost up to $65,000 per intersection for an adaptive system. There are 7 intersections on the system now. Typically, a traditional adaptive system would cost at a minimum $20,000 per site and up to $65,000 per site depending on what system we would have chosen.
The Peer-to-Peer Adaptive Signal Control System in Moab, Utah received the 2016 Innovation Award from UDOT, who is always looking for "new and better ways to do more with less."