The City uses an objective evaluation process to assess requests for installing traffic signals. Considerations include:

• Side street vehicle volumes (side street > 400 vehicles/hr)
• Side street delays experienced by drivers (side street delay > 40 seconds)
• Proximity to adjacent signalized intersections (distance > 200 meters)
• Impacts of backed up (queued) traffic
• Safety concerns / collision history
• Performance measures of the unsignalized intersection
• Impacts of signalization on the neighbourhood (e.g. will not promote shortcutting)

This evaluation provides a means of determining whether a traffic signal is an appropriate level of con trol at a given location, and ensures that available resources are allocated to critical locations in an equitable manner.

Traffic signals are not installed to reduce speeding. When a signal is installed speeding will often increase as drivers accelerate to make it through the intersection before the end of their green interval. Other traffic calming methods should be considered as an alternative to signalization.

Yes, most traffic signals in the City are coordinated in order to minimize stops and delays. Ideal or "perfect" signal coordination is often difficult to attain due to varying speeds, congestion, the distance between signals and varying amounts of green time at each intersection. "Perfect" coordination for one direction of travel results in frequent stops and delays for the other direction.

When traffic volumes are relatively balanced, the traffic signals are timed so that the "reds" and "greens" are balanced in both directions. When the traffic flow is heavier in one direction, the signals are co-ordinated to favour the highest volume of vehicles. For example, a vehicle on 97th Street, travelling towards downtown during the morning rush period should arrive at more green lights than vehicles leaving the downtown via 97th Street during the same time period.

Signals along the South LRT (Light Rail Train) corridor are not coordinated. North and south coordination is provided by LRT pre-emptions of the signal.

Although left-turn phases benefit the turning vehicles, they increase delays for other vehicles and pedestrians using the intersection. Introducing additional phases to a signal sequence results in longer cycle lengths and reduced time available for other movements that are often heavier. Left turn phases are therefore only operated during time periods when left turn demand and delay is high, and there is sufficient intersection capacity to accommodate the additional phase.

The City has an active program of identifying, monitoring, and prioritizing left-turn phase installations at locations that meet City guidelines. This ensures that available resources are allocated to the most critical locations.

This type of left-turn phase, known as "protected-prohibited" is designed to separate left-turning traffic from opposing through traffic. Even if an acceptable gap exists in the oncoming through traffic, vehicles are required to wait for the green arrow in order to turn left.

"Protected-prohibited" phases are currently operating in Edmonton at intersections such as but not limited to Yellowhead Trail & 149th Street and 87th Avenue & 170th Street. These turn phases are implented for safety-related reasons where double left-turn lanes exist, where there are a high number of left-turning accidents, where turning vehicles cross LRT tracks, or where other safety issues are present.

For safety-related reasons, the majority of traffic signals in the City are not put on flash at night. A flashing traffic signal may cause driver confusion, provides no pedestrian protection and may increase the incidences of "drag racing".

The City does however have vehicle-actuated traffic signals at many intersections in Edmonton. At these signals, the light remains green for the main street traffic until side-street traffic is detected. This operation results in lower overall vehicle delay.

Traffic signals in Edmonton are divided into groups called networks. There are currently more than forty networks in the City. Examples of some of the networks are "Downtown", "Millwoods", "University", and "Castledowns". All of the traffic signals within a network typically operate the same schedule of "timing plans" throughout the day. For example, within the Millwoods network, there are traffic signal timing plans for the "AM Peak", "PM Peak", "Off Peak" and "Night".

As each intersection can have several different timing plans, you may notice that the signal timings are different in the morning than in the afternoon. This explains why a left-turn phase might operate at a particular signal in the morning but not during the evening.

Signal pre-emption is a temporary interruption of normal signal operation in order to accommodate emergency vehicles, or to clear traffic from at grade railway crossings. Pre-emption along LRT corridors and at signals near other at grade railway crossings is triggered when a train passes over detectors upstream of the signal. Once a train has been detected the signal will clear directions that can have queued vehicles on the tracks then give a green light to movements that do not intersect the tracks until the train has passed.

The LRT has been given priority over vehicular traffic along this corridor to ensure efficient operation and promote LRT use. Delays experienced along the SLRT corridor are a result of random arrival times of LRT trains. The LRT pre-empts the signal before it arrives at an intersection ending phases that cross the tracks and giving green to north and south traffic. Any intersection along the corridor can be pre-empted consecutively by 2 or 3 trains (in alternating directions) resulting in considerable delays for minor movements during peak LRT periods.

The City has adopted the use of pedestrian countdown signals as standard devices at signalized intersections. These devices are installed at every new intersection, at intersections where 2 or more traffic signal poles are replaced / relocated, or at existing intersections based on a priority program. The priority program considers locations where the devices will be most beneficial to pedestrians such as: locations near seniors’ centre or residences, medical facilities, elementary and junior high schools, high pedestrian activity intersections, etc. All signalized intersections will be equipped with the countdown device in due time.

Although pedestrian signals including the countdown timers are designed for pedestrians, not vehicles, drivers do sometimes look at these lights as an advance-warning tool. Drivers should instead use the signals amber and red intervals as an indication of an impending change in right of way. The City follows a standard guideline in its design of amber and red periods for traffic signals. The amber period provides time for drivers to react to a signal change and decide whether to stop or to safely proceed through an intersection. The red period, where all directions face a red display, provides additional time for vehicles already in an intersection to clear before opposing traffic enters.

The walk light indicates when it is safe for pedestrians to begin crossing. In Edmonton, the duration of the walk light may be as short as seven 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. Once the flashing red hand is displayed it is not recommended for pedestrians to begin crossing as there may not be sufficient time remaining to cross the street safely. Pedestrians should then wait for the next walk light to cross.

Audible signals are provided at key signalized intersections to assist the visually impaired to cross the roadway. The Canadian National Institute for the Blind (CNIB) encourages visually impaired persons to cross based on traffic noise as opposed to a reliance on audible signals. These signals are generally used only in special circumstances such as when the intersection geometry is unusual or vehicle-turning volumes are high. The City coordinates locations for audible signals in conjunction with the CNIB.

In order to minimize stops and reduce vehicle delays on high traffic corridors, many pedestrian signals are coordinated with adjacent traffic signals. Once the push button is pressed, an indicator light turns on to let the pedestrian know that a "call has been entered". The pedestrian must then wait for the walk light to be displayed. Pedestrians should note that pressing the push button more than once will not display the walk light any sooner. The wait time at co-ordinated pedestrian signals depends on when the button is activated in the "signal cycle" and could range from an almost instant response up to a wait of more than a minute.

"Walk/Don't Walk" signals that are automatically displayed are installed at intersections where the duration of the green light required for vehicle traffic in a given direction is greater than the required pedestrian crossing time. At intersections where the required minimum vehicle green time is less than the pedestrian crossing time, pedestrian push buttons are installed. If the pedestrian button is not activated, the duration of the green light can be extended for the high volume vehicle movements. This operation allows for reduced delays to traffic.

A pedestrian scramble phase allows pedestrians to cross an intersection in every direction, including diagonally, at the same time. Pedestrian scramble phases are beneficial when heavy pedestrian traffic and vehicle turning movements by reducing the number of conflict points. This type of phasing significantly reduces vehicle capacity and increases delay and congestion; therefore, intersections are independently evaluated to determine the effectiveness of a pedestrian scramble phase.

If you notice a malfunctioning traffic signal within Edmonton city limits, please report it immediately to EPCOR at (780) 412-4500. Only phone reports are accepted to ensure speedy repair.

The public is welcome to contact the City's traffic signal engineers to discuss any concerns.

Phone: (780) 496-4506

Email: TransportationOperations@edmonton.ca