Getting a Grip on Some Slippery Road Safety Questions

We received a couple of questions recently about traffic and traction. This isn’t the typical type of traction query we get this time of year (most of those are focused around winter tires and chains). To paraphrase, the first question went something like this:

With lots of use, do paved roads get more slippery over time?

It’s an interesting question, and one that intuitively makes sense. If you have a lot of traffic travelling a road, all that friction should gradually wear the pavement down smooth, creating a slippery surface.

Thankfully, the engineers that design our roads have taken that possibility into account and have developed strict standards about the type of rock used in our pavement – they need to be durable and angular to provide the best traction possible. Softer rocks, which could easily round over time aren’t used.

Smooth ride

In fact, as a pavement ages over time it usually becomes a bit rougher, as the oil becomes more brittle and small cracks start showing up in the pavement. That’s where crack sealing comes in, and that brings us to the second question:

Do roads become slippery after crack sealer has been used?

Every spring, our maintenance contractors seal a lot of cracks in our roads. They usually use about 2 million metres worth every year, so you’ve probably seen these black strips on the road.

Once the sealant is applied, loose sand is put on top. The sand prevents the sealant from sticking to the tires of passing cars while it is curing, helps the sealant bond with the rest of the road surface and increases traction for vehicles that drive over it after the sealant has set, which takes a few days.

Smooth ride 2

During that time, the sand can be an inconvenience and can make the road surface more slippery than normal. So if you see some recently sealed cracks, you’ll want to reduce your speed and drive a little more carefully. After the sealant is ready, our maintenance contractor will sweep the excess sand away.

Do you have any other highways questions you need answered? If so, leave us a comment below, or connect with us on Facebook and Twitter and leave us a question.

6 comments on “Getting a Grip on Some Slippery Road Safety Questions”

Leave a Reply to tim Cancel reply

  1. Why don’t we use the same type of reflectors that Washington state uses? They seem to be easier to see in the rain. I’ve noticed many roads here it’s extremely difficult to see the whole lines in moderate to heavy rain.

    Reply
    • Thanks for your comment Tim. Just to be clear – is there are road you have seen with 3 foot deep cracks in it and no road bed under? We would like to follow up if this is the case. Normally a road is constructed with a base and if a layer of pavement is on top of another – there should be a base underneath both layers?

      Reply
      • If you know the history of West Caost Road, West or North to some of Jordan River, the road is an old logging road that took the path of least resistance and never packed the road bed, it used old logs for fill. Those old logs are rotting. Sections of the road the size of cars both lanes wide have sunk and one of the cracks I hit so hard it has knocked out my alinement. I stopped and went back to look at it, the crack is two inches wide in three places on this one patch that is nearly 2 inch drop in road elevation. I looked down the cracks and there is no bottom. I think the whole lane will wash out off the side of the cliff. Both sides of Jordan River is sand and the raod will give real soon. Just drive it – it’s been bad for years and is getting worse by every rain storm and heavy traffic volume.

        Reply