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Variable Speed Limit Decisions

​​How our Transportation staff determine when to raise the speed limit on Whoop-Up Drive back to 90 km/h after a snow event:

  • Once the limit has been lowered, we want to avoid the confusion that could result from moving the limit back and forth within several hours due to changing road/bridge​ conditions.
  • When conditions start to improve, some motorists want us to raise the limit back to 90 km/h immediately.
  • But even when conditions look good during the day, the risk of flash freezing on the bridge deck may still exist, especially early in the morning or late in the afternoon when traffic is heaviest.
  • Before we raise the speed limit, we want to be certain that road conditions and the bridge deck temperature have sufficiently stabilized that a speed limit reduction likely won’t become necessary unless the weather changes.
  • When it comes to the safety of motorists, if we err, it will be on the side of caution. Your safety is our primary concern.
  • We monitor the forecast and conditions and make the safest decision we can. While we hear from those who want the limit raised sooner, we also hear from many others want it to stay reduced to 60 km/h.
  • To provide some perspective, the speed limit reduction adds just over a minute to the Whoop-Up Drive commute.​

When winter weather hits, our goal is to help motorists get around Lethbridge as safely as possible. Here are some winter driving tips:

  • Always adjust your driving for winter road conditions
  • Slow down
  • Stay a safe distance behind the vehicle in front of you
  • Stay a safe distance behind snow plows and sand trucks
  • NEVER pass a snow plow or sand truck 

Our snow crews are ready to mobilize whenever snowy weather arrives:

  • All winter, our snow operations centre is staffed around the clock, seven days a week.
  • We use technology to:
  1. Monitor approaching weather systems
  2. Monitor temperature and road conditions on the Whoop-Up Drive bridge - Bridge decks become slippery when they freeze. Sensors in the bridge deck alert our staff whenever the deck surface is about to freeze, and this informs our decisions on raising or lowering the Whoop-Up Drive speed limit.
  3. Remotely control variable speed signs and message boards along Whoop-Up Drive
  4. Monitor the movements of sanding and snow clearing equipment 

While it's snowing, snow crews will focus on Priority 1 routes throughout Lethbridge:

  • Priority 1 routes are high-volume, main arterial roads such as Whoop-Up Drive, University Drive, Mayor Magrath Drive and 26 Avenue North.
  • Priority 1 routes are determined based on traffic volume and road incline.
  • Snow crews will shift their focus to lower priority routes after a snow event ends and all Priority 1 routes are plowed and sanded.

Want more information on our Snow and Ice Control program?

​​​​Snow and Ice Control Frequently Asked Questions​