Content - Residents - Roads & Traffic - Traffic Signals
Learn more about traffic signals and their use in Kingston by selecting one of the headings below.
How does the City determine where to install traffic signals?
The decision to install a traffic signal is based on Ministry Transportation Ontario (MTO) guidelines that consider traffic volumes, delays, pedestrians and collision history. The cost to install a new traffic signal can range from $150,000 to $220,000.
Why are there cameras on poles at some intersections? Are we being watched?
There are two types of cameras that may be seen on poles throughout the City – traffic-counting cameras and vehicle-detection cameras.
Traffic-counting cameras are used to conduct detailed traffic counts that include pedestrians, cyclists and vehicles. A traffic-counting camera is strapped to a pole adjacent to an intersection and typically remains in place for only two to three days. The digital film is uploaded and processed by a company in Waterloo called Miovision and the traffic counts are sent back to the City. City staff do not have the ability to view the digital film and the public's privacy is respected at all times.
Vehicle-detection cameras that improve the efficiency of intersections have been installed at many traffic signals in the City. These cameras detect the presence of vehicles and allow traffic signals to respond to changes in the traffic volumes by varying the length of green lights.
For example, cameras on Alfred Street at Concession Street allow the traffic signal on Concession Street (a very busy street) to remain or "rest in" green until a vehicle is detected by the cameras on Alfred Street. If only one or two vehicles are waiting on Alfred Street, the camera will cause the traffic signal to operate a short green light. At busier times of the day, the camera will allow the traffic signal to operate a longer green light for vehicles on Alfred Street.
At all intersections outside of the downtown core, if cameras are not in place, magnetic loops imbedded in the pavement detect the presence of vehicles and allow the length of green lights to vary with traffic volumes. The vehicle detection cameras are not recording information and the City does not have the ability to watch traffic at this time.
Can signals be timed so that vehicles can get more green lights?
When traffic signals are co-ordinated, they are timed such that stops and delays for motorists are minimized as much as possible. Some of the factors that affect signal co-ordination are vehicle speed, distance between intersections, congestion and the variable length of green lights on the main street and on the side streets. As traffic signals are usually co-ordinated for the posted speed limit, motorists driving well above or below the speed limit may find that they arrive at more red lights.
Ideal or "perfect" signal co-ordination is usually possible on one-way streets such as Brock Street and Johnson Street. On two way-streets, perfect co-ordination is usually not possible for both directions of travel. For example, if the traffic signals along Gardiners Road are timed so that northbound vehicles always arrive at green lights, then the southbound vehicles would have to stop at several red lights and vice versa. Where traffic volumes are relatively similar in both directions, the traffic signals are timed so that the "red light arrivals" and "green light arrivals" are balanced as best as possible in both directions. When the traffic flow is much heavier in one direction, the signals are co-ordinated to favour the flow of the highest number of vehicles.
Why are some left-turn green arrows so short?
Although left-turn arrows do benefit turning vehicles, they increase delays for other vehicles using the intersection. As there are only so many seconds of "green time" in an hour, the operation of a left-turn arrow requires "stealing" green time away from another direction of travel. In many instances, vehicle volumes are so high in other directions that it is not desirable to take time away to make the left-turn arrow longer.
At some intersections, more time can be added to the left-turn arrow in order to reduce delays. At many intersections however, we need to work within a specific "cycle length" in order to keep the signals coordinated and working together along a corridor. For example, the cycle length along Gardiners Road during the afternoon peak period is 125 seconds. This means that the amount of time it takes to display all greens, ambers and reds in all directions is 125 seconds from start to finish. If 5 seconds is added to a left-turn arrow, 5 seconds must be taken away from another direction so that the cycle length is still 125 seconds. Often the other directions are even more congested than the left-turn lane being considered so we choose not to extend the length of the arrow. The design of traffic signal timings, especially during the busy periods of the day, is a delicate balancing act.
Why can't green lights at busy intersections just be made longer?
In order to maintain co-ordination between a specific group of traffic signals, each traffic signal within the group must operate the same "cycle length". The cycle length is the total number of seconds required to service all the directions of traffic once and includes green arrows, green lights, amber lights and red lights. Cycle lengths in the City of Kingston vary from 70 to 130 seconds.
If more green time is added to one direction, the same amount of green time must be taken away from another direction so that the cycle length remains the same. For example, if the length of the green light for northbound and southbound vehicles on Gardiners Road at Taylor Kidd Boulevard is increased by 10 seconds, then a total of 10 seconds must be taken away from another direction of travel such as the east/west movement on Taylor Kidd Boulevard or time could be take away from a left turning arrow. As these other directions of travel can also carry high volumes of vehicles, it is important to balance the delays for all users of the intersection.
If all of the green lights at an intersection were simply made longer, the cycle length would have to be increased. Motorists would get longer green lights but would have to wait at longer red lights in order to get those green lights. This would result in increased delays and longer vehicle queues.
Can green lights be automatically extended when there are more vehicles at an intersection?
In order for traffic signals to respond to changes in demand, the City has vehicle detection loops, buried underneath the pavement, or vehicle detection cameras at the majority of signalized intersections outside of the downtown core area. The "magnetic inductive loops" under the pavement respond to the metal content in vehicles and "tell" the traffic signal controller to extend the length of the green light when the vehicle demand exists.
Vehicle detection is ideal at intersections where vehicle volumes fluctuate throughout the day as they reduce delays and improve the overall efficiency of the intersection. For example, if there is detection near the stop bar of a left-turn lane and no vehicles are present, the left-turn arrow should not be displayed. By contrast, if there is a long queue of vehicles in the left-turn lane, the green arrow will stay on as long as vehicles continue driving over the detection zone to a programmed maximum number of seconds. At busy intersections, motorists may notice that the length of the green arrow often reaches the maximum time before all of the turning vehicles are serviced.
How should drivers react to the amber light?
Drivers approaching an amber signal indication are required by law to stop unless the stop cannot be made safely. Under ideal circumstances, a motorist sees the amber signal and has adequate time to come to a comfortable stop. In some cases however, motorists are caught in the "dilemma zone" and must quickly determine if they are able to come to a comfortable and safe stop or if they should continue through the intersection.
To separate the vehicle movements for all directions of travel at traffic signals, a clearance period between opposing green lights must be provided. This clearance period typically includes 3 to 5 seconds of amber time in addition to an average of 2 seconds of "all-red time" when all vehicles at the intersection have a red light.
Why can't traffic signals just be placed on flash at night?
The City does not operate traffic signals in flash mode (amber flash on the main street and red flash on the minor street) during quieter hours of the day for the following reasons:
In flash operation, there is no pedestrian protection since the pedestrian lights no longer function. Since pedestrians could be crossing at any time of the day or night, it is still important to maintain a consistent level of protection for pedestrians.
If all of the traffic signals along a major corridor are in flash operation, motorists on the main street would face a flashing amber light at every intersection. Since the flashing amber provides the right-of-way to that direction and requires no stopping, a "drag strip" effect could be created since motorists would soon learn that they could drive the entire length of a corridor without stopping.
When signals are in flash mode, motorists can become confused with respect to who has the right-of-way. This confusion can lead to an increase in collisions. For this reason, vehicle detection is used such that traffic signals typically "rest in green" on the main street and only turn red when a pedestrian, cyclist or vehicle is detected on the side street.
How do walk lights for pedestrians work?
The walk light indicates when it is safe for pedestrians to begin crossing. The duration of the walk light may be as short as seven to ten seconds but can often be greater when the duration of the green light for vehicles is relatively long.
The walk light display is followed by a red flashing hand known as the "clearance phase". The duration of the clearance phase is dependent on the width of the road being crossed. If a pedestrian steps off the curb and begins crossing just as the red hand starts flashing, there should be adequate time for the pedestrian to finish crossing. If the flashing red hand appears when you are only part way across the street, you should continue crossing as there is still adequate time to clear the intersection. If a pedestrian starts crossing after the red hand starts flashing, there may not be adequate time to cross safely.
Pedestrian countdown devices are useful at signalized intersections since they let pedestrians know how exactly many seconds they have left to cross the road. The City is currently installing pedestrian countdown devices at most major intersections.
Do pedestrian lights and countdowns let drivers know when the traffic signal is going to change?
Although pedestrian signals are designed for pedestrians, not vehicles, drivers often look at these lights as an advance warning tool. If a driver is approaching an intersection where the signal ahead is green and the walk light is on, the "clearance phase" for pedestrians has not begun. A driver then knows that the green light ahead is not going to change to amber for a little while longer.
If a driver approaches an intersection where the signal ahead is green and the red hand on the pedestrian fixture is flashing, the driver does not know when the light will change as the duration of the clearance phase is different at every intersection.
The pedestrian countdown devices are timed to allow pedestrians enough time to cross the street. In the downtown area, the traffic signals operate with "fixed timings" meaning that the length of the green lights stay the same throughout the day and do not respond to changes in the traffic flow. At these downtown signals, the "zero" on the pedestrian countdown is always displayed at the same time as the amber for vehicles. Outside of the downtown area, all of the traffic signals are programmed to respond to changes in the traffic flow. For this reason, the length of green lights is variable so the "zero" on the pedestrian countdown does not always correspond to the amber for vehicles.
Where pedestrian countdown devices are in operation, motorists should be aware that the when the countdown reaches "0", it may or may not correspond to the beginning of the amber light for vehicles. Drivers therefore need to focus on the traffic signal intended for vehicles as opposed to the signals for pedestrians.
Why are there pedestrian push buttons at some crosswalks and not others?
At intersections with pedestrian push buttons, it is very important for pedestrians to push the button so that the walk light will be displayed and so that enough time will be provide for the pedestrian to cross the street.
Pedestrian push buttons are installed at intersections where the required minimum vehicle "green light" time may be less than the required pedestrian crossing time. For example, if only two cars are detected on a sidestreet, the length of the green light required for those vehicles may only be 10 seconds. If a pedestrian needs to cross at the same time as those two vehicles but doesn't press the button, the pedestrian will only get 10 seconds to cross the road. If the pedestrian pushes the button, the length of the green light will automatically be increased from 10 seconds to whatever amount of time is required for a pedestrian to cross that particular street.
Why do vehicles on a minor road sometimes have to wait so long for a green light to get onto a major road?
In order to reduce delays and red light arrivals, the traffic signals along most major corridors in the City are co-ordinated and timed to work with adjacent intersections. Since high volumes of traffic on major roadways take priority over lower volumes of vehicles on the intersecting minor road, vehicles on the minor street must often wait until the main traffic movement on the major street has travelled through the intersection.
I am visually impaired. How do I get audible pedestrian signals installed at a traffic signal?
Effective January 1, 2016, the City must install audible pedestrian signals for visually impaired people at all new and rebuilt traffic signals where a marked crosswalk is present. Requests for audible signals at existing traffic signals may be forwarded directly to the traffic division for consideration.