Syncing traffic lights: Tech fixes, enduring challenges

Seeing red? You’re not alone, but the solution isn’t easy


If you drive in Edmonton, you likely know this feeling. You’re on your way somewhere, probably in a hurry, and you find yourself having to stop at every… single… intersection. So, what is actually going on here? And can it be improved?

Why does it seem like Edmonton is horrible at traffic light timings?

It’s difficult to say if in fact Edmonton is worse than other cities at traffic light synchronization. But it is certainly a reality that traffic light timings are vexing to many people. The city received 1,636 complaints on signal timing in 2016, which accounted for about 26 per cent of all the traffic light & sign-related complaints to the city that year, according to the open-data catalogue’s list of calls to 311.

That compares to 6,939 complaints on potholes in 2016, which accounted for 35 per cent of all complaints about roadway operations.

Since 2013, the number of signal timing complaints have been going up:

While many cities track 311 requests, most lump signal timing into other categories, making a comparison difficult. An analysis of Toronto's data shows that city received at least 874 complaints on signal timing in 2014 (the most recent year for which 311 data was available).

It is certainly an issue that comes up elsewhere, from Murrieta, California, where traffic light timings irked local drivers to Pune, India, where smart technology is being introduced in an effort to better synchronize traffic signals.
Edmonton, like all major Canadian cities, has hundreds of lit intersections to manage traffic throughout the city. During those peak hours, some of the intersections can have thousands of vehicles drive through during peak hours.
According to the city’s website, “ideal or ‘perfect’ signal co-ordination is often difficult to attain due to varying speeds, congestion, the distance between signals and varying amounts of green time at each intersection. ‘Perfect’ co-ordination for one direction of travel results in frequent stops and delays for the other direction.”
And it’s not just managing the movement of cars, says Michael Vauden, senior engineer with the City of Edmonton’s operations, parks and road services department.  
“I think that people don’t always realize how complicated it is and how many competing interests there are,” says Vauden. “We are trying to manage cyclists, transit, pedestrians and vehicles.”

What is actually happening when I pull up to an intersection?

It depends on where you are. About 30 per cent of the city’s intersections operate on a fixed-time control traffic light system, with an internal clock programmed to change the traffic lights to meet the demands of vehicles on the road throughout the day.
Engineers use traffic managing software to program the lights using traffic volumes that are counted every four years (sometimes more frequently). The lights along busy roads like Jasper Avenue will remain green for longer to keep traffic moving during peak travel times. That also means that if you’re trying to cross that road, whether you’re in a vehicle, on a bike or on foot, it’s going to take longer for the lights to go your way.
An example of this kind is 97th Street southbound during morning rush hour. If you’re heading south, you’re more likely to get green lights than someone heading east to west or heading north on 97th Street.  

What about the rest of the intersections?

The majority of the city’s streets run on what’s known as a dynamic or actual traffic light control system. Lights will turn green shortly after a vehicle drives over the sensor loops of wires found on some city streets or by driving past roadside sensors mounted on nearby poles.
An example of this kind of intersection is at 110th Street and Jasper Avenue. The street is equipped with a sensor even for bicycles so that the light turns green in their favour as well as for motorists.

Traffic light controller. Photo by Dennis Haslam.

Traffic light controller. Photo by Dennis Haslam.

Can anything be done to make intersections work better?

The city is currently investing in the way traffic lights (both fixed and dynamic) communicate with the main Traffic Management Centre, the traffic control headquarters in Edmonton. These upgrades will allow staff to better monitor and control the traffic lights at major intersections.
Many of the city’s traffic lights still transmit to the Traffic Management Centre via outdated copper wire. That’s being replaced with a wireless system — so far, about 35 per cent of the city’s traffic light system has been converted to wireless.
Once installed, the wireless system will allow for more efficient transmission to the Traffic Management Centre and will save the city some money, according to a Transforming Edmonton blog post.  
It’s a huge project that Calgary is also undertaking, with our neighbours to the south upgrading to the faster but also more expensive fibre-optic lines. Through those upgrades, city officials in Calgary are optimistic it will mean more efficient commutes for drivers through better synced traffic lights.

Is there anything I can do as a driver to hit more green lights?

Traffic lights that change after a certain amount of time are scheduled based on traffic volumes for a given time of day and for the speed limit of the road. If your speed differs too much from the posted speed limit, you're more likely to get out of sync with the lights.

New technology out of the University of Alberta might be of assistance.
It’s called connect-to-vehicle technology and it’s already installed in Edmonton. It isn’t connected to any vehicles on the roads yet, but researchers are expecting this in-car tech to revolutionize how drivers travel.
“When a driver approaches an intersection, this technology will tell drivers how many seconds at a green or red light they have. It can help alert drivers to stop,” says Dr. Tony Chu, associate professor with the university’s department of engineering.
So how does it work? Picture this: You pull up to a red light in your 2018 model vehicle. Since your vehicle is brand new and a specific car model, it will have technology built into it that will trigger a roadside sensor. In turn, the sensor will communicate with your car’s technology to tell you how many seconds or minutes until the light turns green via an audio message or a message on your car’s onboard computer screen.
It also works when travelling through an intersection on a green light, with the possibility of a countdown inside your vehicle telling you when the light will turn red.
The sensor on the road has already been installed along 23rd Avenue at 109th Street as part of a pilot. It’s early days still, but researchers say this could be used by drivers by the end of this year if talks with a specific, undisclosed major car manufacturer are successful, says Chu. If all goes well and the technology is approved, it would make Edmonton the first municipality in Canada with the innovation. Las Vegas became the first city in the U.S. back in December of last year to launch the same technology that connects traffic lights to cars. Car manufacturer Audi became the first car company to install the technology inside some of their vehicles in Sin City.
Chu added that considering the size of Edmonton and its traffic woes, the city could benefit immensely from a better traffic light system that could make it safer for all users of the road by encouraging people to slow down if they know when the light will turn red.
“This will reduce congestion, improve safety and reduce emissions as well,” says Chu.

Green lights down Jasper Avenue. Photo by Walter Gordy.

Green lights down Jasper Avenue. Photo by Walter Gordy.

What else affects the synchronization of traffic lights?

Edmonton installed a pre-emptive traffic light control system to allow fire trucks to make it through intersections more quickly. This is great for emergency response, but it does mean traffic lights along the affected route get temporarily out of sync.
There are also several intersections (approximately 64 in total, with more coming according to city officials) in Edmonton where a bus will trigger a red light for opposing traffic and will allow for the bus to get a head start. One example is along Stony Plain Road and 124th Street, where buses will get to leave the intersection four seconds ahead of other traffic vehicles.
There are also intersections in the city where there are roadside sensors triggered by passing bikes, like the aforementioned intersection at 110th Street and Jasper Avenue.

What about making intersections better for cyclists and pedestrians?

Some say the city should start with simple changes at intersections across the city to reduce the number of potential conflicts between the needs of pedestrians and the needs of motorists. Anna Ho, who chairs Paths for People, says a slight timing change to give cyclists and pedestrians a head start could make a huge difference.
She cites the intersection at 109th Street south of the river as an example. It’s arguably one of the most complex intersections in Edmonton, with motorists coming off the High Level Bridge, runners crossing the street, and cyclists also riding through the area. So when the light turned green, all modes of transit were using the roadway and that was “causing potential conflicts,” says Ho. But the city changed the timing of lights to now give pedestrians and cyclists on the east crosswalk the right away for seven seconds before northbound cars are allowed to travel through.
“In general, traffic signals don’t have pedestrians and cyclists in mind,” says Ho. “The lights are just for motorists. If we step back to see how other modes are affected, we could improve how our road system works for everyone.”

Why should we care about having better synchronized traffic lights?

It’s certainly less irritating than starting and stopping. Less time spent idling at red lights means less carbon emitted, too, which is better for the environment.
But it may not be a panacea. Los Angeles spent 30 years and $400 million to become the first major city to fully synchronize its lights. Early estimates after the new system was introduced “boast a 16 per cent increase in traffic speed, as well as a 12 per cent reduction in delays at major L.A. intersections.” But the city’s traffic remains the worst-ranked in America, and some speculate that induced demand is at work — improvements to traffic flow merely encourage more people to drive, which increases congestion again.

Closer to home, the city of St. Albert receives complaints about traffic signal co-ordination, despite spending hundreds of thousands of dollars on video detection at intersections to improve signal timings. As then-transportation co-ordinator Dean Schick told the St. Albert Gazette in 2011, “I can guarantee you, at any given time, I’m only making 50 per cent happy, at best, at an intersection.”

Is this a new complaint?

No. In 1997, Coun. Allan Bolstad asked city administration what could be done to improve traffic light synchronization, as it seemed that the system was not keeping up with the city’s improved economy and growing population.
“Time is money,” the Edmonton Journal quoted him saying. “The system needs to be updated as the traffic flows change and as changes are made to the road network ... it has a direct impact on how this city functions.”
Brice Stephenson, the manager of transportation planning at the time, noted that traffic systems in Mill Woods, along Manning Drive and in west Edmonton were overdue for an upgrade, as the usual five-year cycle lengthened to almost 10 years due to slow economic growth in the early 90s.
Still, the report in response to Bolstad’s query echoed the refrain of many involved in this field: ‘It's not possible to ensure that no stops will occur when dealing with two-way or network co-ordination.”

Will we still have this problem 20 years from now?

Some are putting a lot of hope on self-driving vehicles to change the ways we think of intersections in our cities.
MIT designers have suggested a slot-based road system, where self-driving cars “can talk to a control point in the intersection, much like planes can talk to air-traffic tower.” In theory, this type of system “allocates a timed ‘space’ for each car, and a car can’t enter the intersection until its slot is ready. In practice, this allows the intersection’s brain to fine-tune the speed of every vehicle that enters it, letting them slip past each other,” writes Fast Company’s Charlie Sorrel.

Many American cities have already begun to introduce smart technology within their traffic light systems to soon accommodate autonomous vehicles. “New York, Wyoming, Michigan, and Nevada are among the early adopters, building smart stop lights and roads that can monitor weather conditions,” says Consumer Reports.
But it isn’t just our counterparts to the south who are testing out new technology. Edmonton could soon be added to the list, with city officials eyeing the possibility of making the city a place to test out driverless vehicles.

What can you do?

The city fields roughly 6,000 new inquiries each year on traffic control. If you’d like to join the chorus, call 311 or submit a service request online to voice your concerns.
You can also reach out to your city councillor about a specific intersection.
But you might also want to consider accepting what you cannot change. There are many articles on practicing mindfulness to help get you through your rush-hour commute.

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