Feeling frustrated after getting caught at a red light is common for many people driving, but for Bradford’s town staff, keeping traffic flowing is no simple task.
In order to determine when a traffic light changes from green to yellow to red, and the duration of each phase, staff use an engineering evaluation based on industry best practices and provincial guidelines, which requires collecting data on the volume and direction of vehicles as well as the pedestrian at each signalized intersection in town, and calculating the best timing for each one, while also factoring in driver reaction times, according to transportation manager Joe Coleman.
“The goal is to find a balance between each direction to allow the intersection to operate at as close to an optimum point as possible,” he said in an email, noting that balance can actually shift throughout the day as traffic volumes vary. “Many of our signals do have different timing for various times of the day.”
That could mean a longer green for a majority of drivers going in certain directions during rush hour, but plenty of variables can throw off the balance.
As an example, groups of traffic exiting large commercial plazas onto Holland Street can quickly shift the amount and directional demand put on certain intersections.
“Highly variable traffic volumes, day-to-day and during the day, pose the greatest challenge to get a pattern that satisfies all users. Our goal is to set the signal timing so it works for the majority of times,” Coleman said.
As another example, a pedestrian walk signal is intended to last long enough for the average person to cross the road.
“The corresponding green timing, and walk signal, cannot be shorter than this time even if the vehicle traffic volumes do not warrant such a timing,” Coleman said.
However, as some roads have five to six lanes plus boulevards at the intersection, a crosswalk might be as long as 30 metres or more, meaning a person walking five kilometres per hour would take about 22 seconds to cross on foot, even if all the drivers sharing the green light could clear the intersection sooner.
Another factor is the different types of traffic signals used at different intersections.
Most major intersections in Bradford use fixed-time signals, where staff manually calculate the timing, but some intersections use semi-actuated signals to provide a green light to the busiest street, and only change this when a sensor detects a vehicle or a pedestrian at a red light on the intersecting street.
Some fixed-time signals also use sensors to detect the presence of vehicles waiting to turn left, and determine whether to include an advance left turn as part of the light timing.
Regardless of the type, Coleman explained that staff review the performance of intersections semi-annually or as issues arise and “continuously collect and review traffic data,” leading to frequent changes and improvements as well as seasonal adjustments.
“Traffic management is an ongoing task,” Coleman said. “As the volumes and patterns naturally change, staff need to collect the new data, apply the evaluation processes and modify signal timings.”
There’s a limit to just how much staff can do with typical traffic lights though, which is one of the reasons why the town upgraded the signals at the Holland and Dissette streets intersection in February 2023.
“The data suggested the old technology was operating at its limits and something better was necessary,” Coleman said.
As a result, the typical fixed-time signals and sensors were upgraded to include adaptive technology, which uses cameras and more sensors, like radar, to monitor directional traffic flow, vehicle delay, and even queue lengths.
“We then use this information to make the signals more responsive to changes in traffic patterns,” Coleman said. “This technology also allows staff to monitor live traffic and collect data.”
For those driving through the intersection it means less time spent waiting at red lights, even though the intersection is now handling about 44,000 vehicles during the busiest 12 hours of the day, on average, with capacity for more.
Meanwhile, staff are still fine tuning the timing of the intersection in an attempt to improve traffic flow even more, a task made a little bit easier by the new system’s increased reliability to detect vehicles and collect data.
While Coleman expects the town to expand its use of those adaptive technologies over time, there’s no definitive timeline for that as of now, and he acknowledged the cost to upgrade the typical intersection is a challenge.
Depending on the type of system and complexity of the intersection, the United States Department of Transportation estimates it could cost between $10,000 to $60,000 to add adaptive signal timing to an intersection.
During the March 19 meeting of council, Ward 3 Coun. Ben Verkaik emphasized the importance of improving the “terrible” timing of lights along Holland Street West, and Terry Foran, director of community services, responded that some of the work to resolve the issue will be part of the Holland Street reconstruction.
In the meantime, Coleman said staff are doing what they can with existing infrastructure.
“Signals wise, staff will continue to co-ordinate signals to allow drivers to drive for longer stretches along a particular road without having to stop as often at red lights,” he said.
As a professional who deals with the nitty-gritty of timing the town’s traffic lights, Coleman reminds drivers and pedestrians that “everyone needs to be somewhere.”
“The town’s signal timing are based on the prevailing speeds and clear roads. Speeding, slower drivers, and stopped vehicles impeding traffic cause the most disruptions to smooth traffic flows,” he said.
