Drive Safely on Snow and Ice

 

A short guide to winter driving.

(Disclaimer: This advice is offered only for your consideration, ĎSet Medical Serviceí accepts no responsibility for errors or omissions)

 

Before you Start

  Donít make the journey unless you really have to!!!

  Make sure you have:- Warm clothing, Gloves, Boots,† Hi-Viz reflective vest or coat, A warm blanket, Shovel, Tow rope, A flask of† warm drink or soup, Emergency food, Your mobile phone (fully charged) & let someone know you are making the trip.

  Set off early. Allow yourself the extra time to drive more slowly. Other motorists will be driving slowly, and overtaking may not be an option. You don't need the extra stress of being late for an appointment.

  Clear snow off all windows and mirrors before you set off; you may need to reverse out of trouble.

  Clear front and rear lights, so other people can see you and your signals.

  Use dipped headlights.

  Is it a good time to car-share?

 

 

Other Traffic

  Driving in snow is as much about dealing with other road users, as looking after your own car.

  Watch the behaviour of oncoming traffic; you may have to avoid them if they slide towards you.

  Expect other road users to be unable to stop at junctions.

  Cars approaching a narrowing of the road uphill will not want to stop in case they can't start again. Cars approaching downhill may be unable to stop without skidding.

  Try to leave a 10 second gap between you and the car in front.

  If the car behind is too close, find a good place to stop and let them go on ahead. (Then you can concentrate on the road ahead)

  The 10-second gap allows for increased stopping distances, and gives you time to respond if the car in front has problems.

  If they stop, you may have time and space to steer a different course, or by slowing down you can allow time for the obstruction to clear without having to stop and restart yourself.

Driving on Ice

  Unlike snow, ice is often invisible. You have to guess where it might be.

  Look for reflections in the road surface ahead; what looks like water, may be ice.

  Bright sun and a warm wind can quickly thaw ice, but leave patches in sheltered areas, so be vigilant where a wall casts a shadow over the road.

  If you travel a road regularly, note where water collects on the road and may freeze.

  Road bridges and fly-overís freeze first because they are cooled from below.

  One of the first signs of slippery conditions is if the steering becomes lighter to turn.

  The normal tendency of the steering to self-centre when you let go of the wheel becomes less powerful when the front wheels lose grip.

  If you are aware of this effect, you can feel the reduced resistance to your steering wheel movements as the road becomes slippery.

Skid Avoidance

  Drive gently; avoid harsh acceleration, hard braking, abrupt downward gear changes, or abrupt steering movements. These can all cause a skid.

Avoiding Wheel Spin

  It is difficult to control your car if the wheels are spinning in snow. Try starting off in second gear to avoid spinning the wheels. Accelerate gently and change up early.

  If the wheels start to spin, gently lift off the accelerator until they grip again.

  If you keep spinning the wheels where the road slopes to the side, you will slide sideways down the slope and risk hitting the kerb, a wall, or another car.

 

 

Braking

  Brake gently without locking the wheels.

  If you lock the front wheels they don't steer anymore; the car just goes straight on.††††††††††††††††††††††††††††††††††††††††††††††††††††††††††††††††††††††

  If you have ABS, it will automatically release the brakes momentarily, and then re-apply them to keep the wheels going round enough for you to steer.

  But remember ABS stops working below about 4 mph, so progressively lift off the brakes as you come to rest. Otherwise you may continue to slide slowly and gracefully into an obstacle.

  If you are sliding down a hill, you may have to be brave and release the brake pedal while you regain steering control, then gently reapply the brakes.

  If you don't have ABS, pump the brake pedal on and off to give alternate moments of braking and steering.

  4x4 four wheel drive vehicles can keep going in slippery conditions, but their brakes are no better than an ordinary car, and being heavier, they tend to have longer stopping distances - even in good conditions.

Engine Braking

  You can avoid having to brake by using "engine braking" - select a low gear on down hill stretches. Do this before you begin the descent.

  Normally when you release the clutch after changing down, the car's momentum speeds up the engine to match the road speed in the lower gear. In snow the tyres may not have enough grip to do that, and it can cause a skid.

  So release the clutch gently and use the accelerator to help match the engine speed to the lower gear.

  It is difficult to drive smoothly in first gear. Use second gear unless you are absolutely at crawling speed.

Cornering

 Don't ask your tyres to steer and brake at the same time. They have to share the available grip between those two functions; so either one detracts from the tyres ability to do the other.

  Slow down to the right speed before you get to a corner. Make downward gear changes while you are still travelling in a straight line, then the all the grip of your tyres can be used for steering round the corner.

  Accelerate gently as you go round corners.

  If you are concerned about driving in snow, get your tyres checked now - before you need them. Good tyres can make all the difference between reaching your destination or not, and snow chains will transform the amount of grip you have.

Advanced Snow Driving Techniques

  Find out if your car has front wheel drive or rear wheel drive. (Most small cars are front wheel drive today).

  With front wheel drive, you can use a little power to pull the front of the car around, or zigzag up a steep slope.

  With rear wheel drive, extra power makes the back of the car slide outwards on a corner, and zigzagging will get you in trouble.

Friction:

   Remember that friction between two surfaces increases with the force that presses them together. Put heavy things (like passengers) as near as possible to the driven wheels.

Weight Transfer under Acceleration:

  You have seen dragsters lift the front wheels off the ground entirely under hard acceleration, transferring all of the vehicle's weight to the back wheels.

  To a lesser degree, the same thing happens when a road car accelerates - you may see the bonnet rise a little and the rear of the car squat down.

  In a front wheel drive car, if the back end is sliding, applying some power moves weight onto the rear wheels and helps them grip again.

 

Weight Transfer under Braking:

  The opposite is also true. If you brake, or lift-off the accelerator abruptly, as you turn a corner, it moves weight forward, making the front wheels grip more and the rear wheels light and therefore more likely to slide sideways.

 

 

Handbrake Turns:

  Rally drivers sometimes steer into a corner, and then pull sharply on the handbrake momentarily to lock the rear wheels. This makes them slide sideways, turning the car faster than could be done by steering alone. But before you try this, you need to consider that there is a risk of making matters worse by spinning the car and hitting something sideways. (See "If it all goes wrong" below).

 The handbrake is easier to use in a front wheel drive car because the hand brake does not have to overcome the power from the engine on the rear wheels.  

Reversing Uphill:

  If you are really keen, front wheel drive cars will sometimes climb a snowy slope better in reverse gear, because having the back of the car higher than the front puts more of the engine weight over the driven wheels.

  This unlikely approach does also mean that if you fail to climb the slope, and run out of traction, you are at least facing the right way to control your descent back to the bottom of the hill.

  This avoids the problem that if you fail to climb up a steep snowy slope in the normal forwards direction, you can find yourself sliding down hill backwards.

  The reduced visibility when reversing, means that this method should only be tried if you are sure about the intentions of other traffic.

Skid Correction

  Don't brake! That will make it worse. The simplest response is to ease off on the brake or accelerator and try to keep the front wheels pointing where you want to go.

  Pressing the clutch relieves the tyres of the job of engine braking and makes their entire grip available for steering.

  Skid correction is a skill that is not easily explained in a few words, but there are many training courses available. They make an ideal birthday gift and an entertaining day out for the family.

  Front wheel drive and rear wheel drive cars behave differently.

Front-wheel Drive Skid Correction:

   If the rear end slides, it is fairly intuitive to correct the problem by steering into the skid, trying to keep the car pointing in the direction you want to go.

  But you should also release the brakes and apply some more power, to pull the front of the car back into line, and to use weight transfer to give the rear wheels more grip.

  If the front end slides under heavy braking, you must release some of the brake pressure. An expert would also apply a dab of handbrake, but before you try this, you need to consider that there is a risk of making matters worse by spinning the car and hitting something sideways. (See "If it all goes wrong" below).

  If the front end slides even when you are not braking, then lift off the accelerator - and hope that the front wheels will regain some grip before it is too late.†††††††††††††††††††††

Rear-wheel Drive Skid Correction:

  If the rear end slides, it is fairly intuitive to correct the problem by steering into the skid, trying to keep the car pointing in the direction you want to go.

  But you should also apply less power to allow the rear tyres to use what grip is available to resist sideways motion.

Straightening the steering:

  As mentioned above, the normal tendency of the steering to self-centre when you let go of the wheel doesn't work in slippery conditions.

  This lack of self-centring also means you have to straighten the wheels yourself. In skid-correction it is easy to lose track of which way the front wheels are pointing.

  Professionals sometimes mark the 12 o'clock position of the steering wheel with white tape, so they can easily see where the front wheels are pointing.

  Alternatively the centre of your steering wheel probably has styling or lettering that makes this clear too.

  If you think the steering wheel is straight, but the car is still turning, maybe you are one full turn of the wheel off centre?

Don't over correct a skid.

  A good rule of thumb for beginners is to keep the front wheels pointing where you want to go, unwinding any steering correction as soon as you feel it taking effect.

  If you are too late removing the steering correction, the car may swing violently the other way.

  With front wheel drive, gentle acceleration will always tend to pull the car back onto your intended course.

If it all goes wrong

  If after all your efforts you can't avoid hitting something, remember your car offers you more protection in a head-on crash than a side impact.

  There is a lot more energy-absorbing metalwork between you and the front bumper, than between you and the outside of the door.

  Seatbelts and frontal airbags work much better in a frontal impact, and many cars don't have side-impact airbags.

  If you slide sideways into a kerb or soft ground, your car may roll over (particularly in a tall 4x4 vehicle), whereas if you hit them forwards, you will probably keep going.

  So, travelling sideways is not good: if you are able to turn at the last minute, try to hit things head on.

 If you need towing you may regret not bringing a tow rope. Your Car probably has either a fixed towing eye or a screw type that screws into the chassis probably located behind a small pull out cover .

  If you get totally stuck in snow. Remember that your car is a good, heated, sheltering place. Make sure you have adequate clothing and footwear before leaving it to walk home.

 If possible try and leave your car where it will not be a problem to other traffic & snowploughs

There are plenty of idiots out there,

Donít be one of them

Sources:

FEMA.gov, NOAA.gov, MACCINFO.com

Sources:

FEMA.gov, NOAA.gov, MACCINFO.com