11th February 2014

Blog: Black Ice is not Nice

What it is: 

Black ice is so called because the road surface can look merely wet, masking the fact that a mist layer of water on its surface is clear ice. It occurs when the temperature drops to freezing.

Can I see it? 

Where on a dry road, you will see the frost, it is nigh-on impossible to see Black Ice. Anytime you see a glossy sheen on the surface ahead, you have to be suspicious of Black Ice.

Where is it likely to occur? 

It can remain on sheltered areas I refer to as ‘Micro-climates’, where trees, buildings or high walls, shade the roadway and denying it of direct sunlight.

Black Ice will generally be patchy, with only small sections of roadway affected. Depending on the road, you may have multiple patches, altering your tyre grip many times, thereby making it very dangerous.

Microclimates can be found on most roads. Black Ice areas are more likely to be found on:

  • Roads that wind around lakes and rivers, where water mist is blown onto the road and freezes
  • In tunnels, where water has entered or where condensation has occurred
  • On overpasses, including motorway flyovers where the cold air flowing top and bottom reduce the road temperature quicker than elsewhere, effectively 'Cold-grilling' the driving surface.
  • Black Ice is also prevalent in quiet road areas, both urban and rural, especially in the shaded areas of high walls and buildings. 

Beware of Silence

When tyres run on ice they make virtually no noise, so where the tyre noise reduces dramatically, it is very probably due to ice. Turn down your radio/music and your internal fan – open your window a little and listen.

Knowledge, Preparation & Action

  • Before your journey, get a current weather report
  • Use your local knowledge to your advantage
  • Build Time into your journey
  • Remember you will lose traction through three key areas, Braking, Steering and Acceleration or a mixture of all three
  • We cannot defy Physics, so factors like road camber/cross fall, ascents and descents, all influence the cars behaviour in everyday driving. Where it is slippery underfoot, they can take over!!!
  • Keep a relaxed grip on the steering wheel – no white knuckles!!
  • It is prudent therefore to keep your speed down below that posted
  • Keep a check on the physical behaviour of other vehicles ahead, which can give you clues as to the presence of Black Ice
  • It may seem obvious, but keep a controlled distance back from the vehicle in front, so as to avoid being involved in their bad decisions.
  • Where you notice the ‘silence’ or the steering going light, or the wheels locking up under braking, (ABS will kick in early and you will hear a grating noise and may feel the brake pedal pulsing), are all indications that you are on Black Ice.
  • DON’T PANIC – Recognise what has caused the car to skid. Remember BSA, Braking, Steering, Acceleration
  • If you are Braking, continue to do so if you need to reduce your cars speed, remember to STEER, ABS allow this – Avoid Target-Fixing, where you visually focus on a static object, which you invariably will drive into!!
  • Be mindful that because Black Ice occurs in patches you can go from a no-grip surface to a full-grip surface within a short distance. Look ahead for your exit line – do not Target Fix.
  • If the skid occurs in a corner, during a Steering manoeuvre, ease off the steering as much as you can - wait for the car to straighten up – be ready for it to go into a secondary skid.
  • If your car if fitted with ESP, Electronic Stability Programme, it will correct itself as it detects the car going beyond the point of steering. Check out the link; http://www.youtube.com/watch?v=YjvNxzT31Wc
  • Where your car skids on Acceleration or at any time on application of the accelerator, simply ease off the accelerator pedal. Most cars today have Traction Control Systems, which on detecting the wheels spinning under acceleration kill the power going to the wheels electronically. This is incorporated into ESP.

Remember it is better to know how skids occur and thereby prevent them rather than try to correct it when things go wrong.

 

By Tony Toner, BeepBeep.ie Motoring Correspondent.

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