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Variable Speed Limits on Whoop-Up Drive

​​​​​Did you know that the City of Lethbridge has cameras and sensors mounted by the bridge decks on Whoop-​Up Drive to monitor weather conditions. Images (updated every 5 minutes) as well as road temperature, air temperature and wind speed information can be found below. This information is used by the City when adjusting the variable speed limit signs.

 

Data captured

Sensor ID Surface Temp. (°C) Surface Cond.
Surface data unavailable
Air Temp. (°C) Avg. Wind Speed
Atmosphere data unavailable

​Wondering how we decided when to raise the Whoop-Up Drive speed limit after a snow event? Click here for information.

Lethbridge is among the first Canadian municipalities to implement Variable Speed Limit technology to enhance winter safety on Whoop-Up Drive. Here's a little more information about the technology on Whoop-Up Drive.

Changing weather and road conditions present considerable challenges not only for drivers but also for our Transportation staff who monitor and maintain roads.

From a safety standpoint, cold weather reduces pavement friction, which increases the potential for collisions when vehicles are travelling too fast for road conditions. Snow and ice compound the risk. Under such conditions, the posted speed limit may no longer be safe and appropriate. Although drivers are responsible to adjust their speed for road conditions, new approaches are needed to influence driver behavior when weather conditions make it necessary to slow down.

Among these approaches are the use of:

  • Road/weather condition monitoring systems
  • Variable speed limit signs
  • Electronic message boards

Variable speed limits (VSLs)  can be used to slow down traffic based on road, traffic and/or weather conditions. Identified in the Alberta Transportation 2010 report Methods of Reducing Collisions on Alberta Roads, VSLs have been used to improve the safety of motorists by reducing speeds during adverse driving conditions. It has been documented that use of a VSL system can reduce overall collisions by 45 per cent and injury collisions by 20 per cent.

The City of Lethbridge is one of the first municipalities in Canada to implement a VSL on the 3.5-km section of Whoop-Up Drive that crosses the Oldman River valley. Whoop-Up Drive is a main arterial roadway where the speed limit is normally 90 km/h. It has slopes of six-to-seven per cent on either side of the river and handles an average of 50,000 vehicles each day. In the past, a significant number of collisions occurred during severe snow events. Since the new VSL system was introduced in October 2014, no collisions have been reported on Whoop-Up Drive in winter weather when the speed limit was reduced to 60 km/h.

The road/weather condition monitoring system helps us forecast freezing bridge conditions, and we use the solar-powered, electronic message boards to convey important information to motorists using Whoop-Up Drive.