By Dori Modney (@Dori_Modney on Twitter)

Variable Speed Limit Decisions on Whoop-Up – the reasoning behind it

Dec 22, 2016 | 6:03 PM

LETHBRIDGE – There was a stream of disgruntled comments on social media over the past month regarding variable speed limits on Whoop-Up Drive.

With more snow on the way, the city is educating drivers on the reasoning behind those fluctuations and hoping that understanding will quell the frustration.

City Transportation Operations coordinator, James Nichols, says the decision regarding a speed reduction is made as soon as snow is detected accumulating on the road surface and the probability of icy conditions forming, especially on the bridge decks. As soon as that is detected by technology (imbedded in the roadway several years ago), they will decide to lower the speed limit to 60-kmph.

Nichols noted that even when conditions look good during the day, looks can be deceiving. The risk of flash freezing on the bridge deck may still exist. That’s a factor which is not apparent to drivers.

“The worst times for icy conditions potentially forming on bridge decks are early in the morning and later in the evening when the sun starts to go down, and that tends to be the times when traffic gets heaviest on Whoop-Up, so we always try and keep things simple for people – if there are any conditions that might indicate ice on the bridge decks or even the potential for ice, we tend to err on the side of caution for that.”

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Nichols also pointed out, traffic studies have show that lowering the speed limit from 90-kmph to 60-kmph, only adds one extra minute to your commute.

In order to enhance safety and reduce collisions on a 3.5 kilometre span of Whoop-Up Drive over the Oldman river valley, Lethbridge was one of the first Canadian municipalities to implement Variable Speed Limit (VSL) technology.

Roughly 50,000 vehicles traverse that section of road every day. Since the VSL technology was introduced in October of 2014, no winter weather collisions have been reported on Whoop-Up Drive when the speed limit was reduced to 60 km/h.

More information on the city’ VSL technology can be found on the city website.

by Dori Modney (@Dori_Modney on Twitter)

Variable Speed Limit Decisions on Whoop-Up – the reasoning behind it

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