The City of Grande Prairie Traffic Operations Group is responsible for all things related to traffic flow and safety in the City.

This includes traffic engineering, installation of signs and markings, and signal maintenance. All three components work together to keep traffic flowing in Grande Prairie.

• Traffic Engineering: data collection; traffic modelling; timing optimization; speed limits; assessing signal/crossing need; safety reviews.
• Traffic Sign Shop: sign construction/installation; repairs from knockdowns/collisions; facility/emergency signage; temporary traffic control; roadway painting (crosswalks, stop bars, and lane markings).
• Traffic Signal Maintenance: maintenance of 83 signalized intersections, 10 overhead pedestrian crossings, and 7 beacon-controlled crosswalks; repairs from knockdowns/collisions; emergency troubleshooting; over-dimensional loads; emergency vehicle pre-emption.
  
  

Traffic Signal Operations

Traffic signals are complex systems that require the setting and optimization of a number of different parameters to facilitate smooth traffic flows. Methods of control and timing values are determined by a combination of computer simulation and on-site observation. Some values, such as the length of the amber signal, are determined using factors including the intersection approach speed, the width of the intersection, and incoming sightlines and grades.

The City of Grande Prairie traffic signals run in two distinct modes: free operation and coordinated operation.

Free Operation:

• Has no fixed cycle length.
• Relies on vehicle detection and pedestrian push-button operation to indicate demand.
• Shortens low-demand movements early, reallocating the conserved time.
• Extends high-demand movements to maximize vehicle throughput.
• Reduces waiting when no traffic is present in the opposite direction.
• Is unable to coordinate with surrounding intersections.
• Is used at intersections that are a long distance (>250m) from others.
• Examples: 68 Avenue / 100Street, 84 Avenue / Patterson Drive, 102 Street / 108 Avenue

Coordinated Operation:

• Operates on a fixed cycle length.
• Designates one intersection as the reference point.
• Offsets subsequent intersections by a set number of seconds.
• Comes in two varieties:
  1. Pre-timed – All movements run for a set amount of time, intersections cycle continually (e.g. Downtown)
  2. Actuated – Priority is assigned to main street movements; side streets, pedestrian phases and protected left turns are skipped if there is no demand (e.g. Wapiti Road).
• Can result in longer wait times for side street access and pedestrians.
• Is typically used on major corridors with intersections in close proximity.
• Is most noticeable on one-way streets with short distances between intersections. (e.g. 99 and 100 Avenues downtown)
• Examples: Downtown (99 Avenue Eastbound, 100 Avenue Westbound, 100 Street), Wapiti Road (108 Street)