Imagine never having to stop at a red light again. That was the stated goal of John Njord, former director of the Utah Department of Transportation, when he announced in 2011 he wanted to turn UDOT into a world-class operation. That goal is taking shape thanks to a program that utilizes existing technology, like the Wavetronix SmartSensor Advance and Matrix, in revolutionary ways. So innovative is this technology that the American Association of State Highway and Transportation Officials recognized UDOT with a 2013 Group Focus Award.
The program is called Traffic Signal Automated Performance Measures. UDOT partnered with Dr. Darcy Bullock, professor of Civil Engineering at Purdue University and director of the Joint Transportation Research Program who, along with the Indiana Department of Transportation, paved the way for the program.
Tap to view the Signal Performance Metrics program online
Mark Taylor, traffic signal operations engineer for UDOT, says Njord’s dream of never encountering a red light is the goal that traffic engineers have for everyone, but creating efficient signal plans can be costly and loses value over time.
“Typical modeling and collection methods only provide a limited snapshot view that degrades over time as traffic patterns change,” Taylor says. “We need to know in real time where the problems are so we can make corrections to operations and improve traffic flow.”
Eliminating these problems is what attracted Taylor to a plan that automatically creates performance metrics based on real-time data acquired through existing infrastructure.
UDOT oversees around 16,000 lane-miles of roadway and 1,144 of Utah’s 1,883 traffic signals. Since before the 2002 Salt Lake Winter Olympics, UDOT has worked to build a statewide ITS infrastructure resulting in around 81 percent of UDOT signals and 70 percent of non-UDOT signals sharing a single communications network — including around 750 that are monitored by either SmartSensor Advance or SmartSensor Matrix.
The Automated Performance Measures program utilizes Utah’s extensive connectivity in creative and innovative ways, allowing for real-time monitoring of intersections 24 hours a day, seven days a week. The information gathered from this monitoring provides a wealth of data that populate metrics for traffic engineers and others.
Working with UDOT, Wavetronix optimized the SmartSensor Advance to allow the transfer of raw data directly from traffic signal controllers to a five terabyte UDOT server using an FTP connection, bypassing the need for a central traffic management system. This means the information and metrics can be accessed on any device capable of navigating the Internet, from a top-of-the-line computer to a smartphone. This information is available at udottraffic.utah.gov/signalperformancemetrics. For people using the Chrome browser, Taylor recommends hitting the F5 key once in order to view all of the site’s features.
“That is revolutionary,” Taylor says. “You always had to have the software on your computer. We are completely outside of that and pulling the high-resolution data straight from the traffic signal controller.”
UDOT chose to make the informational metrics available to anyone who wants it without the need for special permission or software, thus helping to fulfill another goal of becoming the most transparent DOT in the United States.
Since its introduction in January 2013, consultants, municipal transportation departments, academics, metropolitan planning organizations and others have accessed the information gathered by UDOT, the benefits of which have been, according to Taylor, incalculable.
In the first nine months of usage in Utah, UDOT proactively found and fixed more than a hundred detector problems and optimized traffic signals from one side of the state to the other. In one instance, UDOT discovered a problem at 700 West Riverdale Road in Ogden. Using a phase termination chart developed by Purdue University, it was discovered that an intersection using video detection was malfunctioning at night, causing lights to max out on nearly every cycle and leaving vehicles waiting at a red light for over 30 seconds with no other traffic. The problem was discovered quickly and repaired when the video detector, which was unable to sense vehicles at night, was replaced by a SmartSensor Matrix.
Problems like this would often go unnoticed for long periods of time because no one was regularly monitoring intersections outside normal businesses hours.
“Before, I would send a technician to check on the detection. He would get there around noon, not see any problem with the signal, leave without doing anything, and write me a nasty note about wasting his time,” Taylor says. “Now, I can tell him that it is the video detection not working in the dark.”
Another example happened when a new coordination plan was installed at 5400 South Bangerter Highway, a busy continuous flow intersection in Salt Lake City.
“We botched it up,” Taylor says. “Our offset was about 180 degrees backwards from what it should have been.”
Rather than improve traffic flow, the incorrect coordination plan caused massive backups, where around 70 percent of traffic had to wait up to a minute for a green light. Using a Purdue coordination diagram populated by real-time data gathered at the intersection, the problem was almost immediately detected and corrected. The incorrect plan started at 9 a.m. on 7 March 2013; by noon that same day, the problem was fixed, with around 70 percent of vehicles going through green lights with no wait at all.
Seventy percent is good, but not good enough for Taylor, who says using the automated performance measures allows for UDOT to be proactive, rather than reactive, when it comes to optimizing traffic flow, until traffic becomes a thing of the past.
The Group Focus awards are given each year from AASHTO to transportation organizations that utilize innovative technology that has the potential to help other agencies. Impressed with the technology behind the Traffic Signal Automated Performance Measures, as well as UDOT’s acknowledgement that innovation, creativity and risk are necessary to meet a growing society’s transportation needs, AASHTO awarded UDOT with one of three 2013 Group Focus awards, an honor that will bring additional expertise and funding to the program.
“Being recognized by AASHTO is a fantastic achievement for UDOT,” says Taylor. “UDOT’s executive leadership has a focus on innovation, recognizing that we cannot always build our way out of congestion. Innovation, creativity and risk taking must be part of the process to meet the demands placed by a society that continues to grow in size and needs.”
