New Tarmac and Ice Driving Have Lots in Common -- Easy Skids

If you've driven along any patches of new or improved Interstate highway or a new or improved parking lot, you have been driving on a paradox. The highway is nice and smooth and great for speed in dry weather, but it is also uncured. This means that any new chemicals that were laid down when the new asphalt was poured have to come out of the roadway.

When does that happen? It usually happens during the first or second heavy rainstorms that occur in the area. And the reason it occurs is the result of the way asphalt is made. It is a combination of things like chopped up rubber, uniform, coal-type rocks, all held together with a petroleum-based glue.

Now, no matter which way you slice it -- up and down or back and forth -- the chemistry of petroleum and water just do not mix. Think about some of the major oil spills that have occurred over the years. As tragic as they were, they also point out that oil is oil and water is water and they will never mix.

So, here we have an uncured section of highway or parking lot that has just been laid down by the huge asphalt machines and pressed into place by multi-ton rolling machines. And it all looks great.

Indeed, the first few cars that use the roadway or parking lot probably report that they can move quite swiftly and surely through the area because there's a great new surface that seems grippier and smoother than other road surfaces these drivers have driven on for some time.

This is a true statement!! As the asphalt cures, it also cools as it starts out incredibly hot and some of that extra grippiness of the highway surface may simple be the fact that the tread of a car's tires is melted somewhat by the cooling surface and the vehicle holds better. That the asphalt will eventually chill out isn't important right now because when that happens you'll find it holds its shape for a few years and then begins to crack and break and the whole process starts again (the replacement process, that is).

So, here we have this stretch of roadway or driveway or parking lot and the first rains start up. What happens next is pretty clear! Since oil and water have the mixing qualities of nothing at all, you'll find that any petro-based products -- fillers, glues, even the asphalt pieces themselves -- begin to shed their petroleum as they get wet and that petroleum does what most oil does in this situation, it heads right for the surface of the roadway or driveway or parking lot.

And, now here's where the "fun" begins, because most people think that everything's all right, but it is not. The petroleum stew floats on a minute blanket of water so that your tires have to not only penetrate that petroleum-based surface, but also the water on top of the roadway.

Now, if you are driving too fast for the conditions -- anything over about 30 really is too fast for this type of roadway -- and unless you have super-new tires with a great, aggressive tread pattern that pushes the juice up and away from the tires center patch, then you are driving on what is essentially a skating rink.

You can tell this is happening shortly after the rain begins because some of the vehicles ahead of yours will create a soapy-looking set of tracks and if they do, back down quickly or get off the highway until the rain stops.

The new, uncured asphalt is simple reacting to the rules of the chemistry of oil and water and water is pushing its way through the cracks and crevices between the new pieces of tarmac and the water is doing its own set of chemistry experiments.

So, the best thing to do, if you can ride it out, is to ride it out at a roadside cafe or just pulled over under a bridge. If you have to drive to get somewhere, then slow down and avoid sudden, jerky movements as you are advised in winter driving because the coefficient of hold is about the same.

These two items are probably your best bets at avoiding anything nasty to happen to your car. However, if you must drive on the new, uncured roadway, slow down and exaggerate your movements. You may have other folks giving you weird looks or honking away. But, let them, they are the ones heading for their dates with the lamppost or abutment. You're not, now, are you?