The Science of Winter Driving

It’s a fact of life that everyone understands, but few question – ice is slippery. You learn this quickly when you are a kid, and learn it even quicker if you end up falling over face first on it. But why is it so slippery?

Well science teaches us that . . . it doesn’t know. Yep, though many plausible theories are present in our world that attempt to explain why ice is slippery, no one quite knows why. The two competing argument are 1) pressure applied to the ice causes water to melt out, and 2) the friction (however minimal) applied is what makes the water melt.

 

Either way, it is the substance that causes the most havoc on our roads. It can make any seemingly safe street into a slip-and-slide very quickly. We already explained HOW BEST TO STAY SAFE this winter, but here is a little more knowledge to explain exactly why we do what we do, and how ice causes other problems.

 

Salt

 

When ice arrives, salt is usually the first line of defence. Why? Because salt does something miraculous – it lowers the freezing temperature of water. Without salt, water freezes at 0°C. But when salt is mixed in, that lowers to -21°C. So layering salt down before the snow and ice arrives, or during the snowstorms first few hours, helps significantly lower the chances of ice forming.

 

Sand

 

However, salt sometimes isn’t enough. If it isn’t laid down quickly, or if temperatures get to -21°C, salt will become a lot less effective. In this instance, highway maintenance crews will start to include sand and other types of grit into their salt mixtures. The salt can still help to prevent more ice forming, but the sand will allow tyres to gain more traction, reducing skidding.

 

Potholes

 

While potholes happen all year round, snow and ice can speed up the process at an alarming rate. The process starts when snow starts to melt. The resulting water will seep into cracks in the road and settle. When the temperature drops again, the water will freeze into ice, expanding out.

 

This increase in size will excavate the crack, making it wider. If this process happens several times, the crack will eventually become a hole. Then, when drivers start driving over it, the hole will start to expand again, until it becomes a pothole. Water can also seep into any gaps under the roads, and once that ice melts, the above road can collapse in when driven over.

 

The Future

 

And these problems have been the reality for several decades now. So can we expect things to get better in the future? Well strides are being made in the fight against icy roads, with one such idea being solar powered roads. The solar panels in the road surface would charge during sunny weather, and then activate when the snow & ice arrives. This is likely to be an expensive endeavour however, so don’t expect it any time soon.

In the meantime, we’ll just have to rely on the good old fashioned approaches. If they were all this efficient, we’d have no reason to worry!

Image credits – Wikipedia.org