A fairly nasty winter storm will be affecting the region where I live today with total accumulation ranging from 3 to 5 inches of snow. So with that being the case I figured it would be a perfect time to write up an article about Winter Driving Techniques so we can make sure that everyone makes it to where they are going safely.
Winter conditions can be unpredictable, however most of the techniques required in cold environments are common sense:
- Keep speed as low as practically possible
- Increase the distance between cars, corners, junctions and any other hazards
- Get all of your braking done on the straights, never brake during a corner
- Be prepared for understeer and oversteer, and know how to correct when necessary
- Be prepared to use ABS or avoidance braking techniques
- Top up washer fluids and antifreeze
- Select ‘snow’ mode if available on automatic transmissions, or if an advanced electronic stability control system is fitted.
Depending on the severity of the conditions, it may be worth considering specialist winter tyres. The difference they make is remarkable. These vary from a Mud and Snow (M&S) rating through to studded tyres for icy roads. Surprisingly, with the correct tires fitted, driving in quite severe conditions can become remarkably easy – you just have to pay a visit to Finland or other northern countries in the Winter for a demonstration.
Manufacturers of winter tyres use several methods to increase friction and help maximize control. Firstly, the rubber compounds are usually softer which allows optimum friction to be reached at lower temperatures (this however does make them wear faster when used in warmer conditions on dry tarmac). The diagram below shows the effect of different rubber compounds on the stopping distances in different temperatures.
Secondly, winter tyres can have small ‘sipes’ which are formed into the rubber within a tread block – these provide grippy edges which are especially useful when driving in snow. Thirdly, the tread tends to be wider and deeper which provides more bite when driving in the snow or on ice.
Winter tires usually also have an aggressive block-like tread pattern which can help to dig into the snow and provide traction (also useful in muddy conditions). Finally, small studs can be fitted to the tire and these provide a great deal of benefit when driving in icy conditions, although in some countries these are only permitted in the coldest months as they damage road surfaces. Studded tires can also increase your braking distance when on a clear dry road.
Pull away and accelerate gently and progressively.
In slippery conditions such as snow and ice, aggressive acceleration is likely to break traction at the driven wheels. The resulting wheelspin can lead to loss of steering control in a front wheel drive (FWD) car, or an oversteer slide in a rear wheel drive (RWD). Both of these situations will prevent you from going in the direction you want and can be difficult to recover from.
Recover from wheelspin
If you do notice wheelspin or the traction control systems fighting for grip, don’t floor the throttle, but instead back off the gas and then reapply smoothly.
Keep the engine speed (rpm) as low as possible
Keep a constant gentle throttle in order to maximize grip. Most diesel engines will cruise along happily in low gears without using any throttle as all.
Reduce torque at the wheels
Change up sooner rather than later, pull away in second gear if possible, and use the highest practical gear at all times. This reduces the torque at the driven wheels and will therefore reduce the chances of wheelspin – also a useful trick when trying to climb a slippery muddy hill. Keep gear changes as smooth as possible – it will be easy to spin the wheels in most gears when conditions are really bad.
Avoid sudden driver inputs
These can include steering, braking, acceleration or gear changes. You only have a finite level of grip available and you don’t want to overload your tyres unnecessarily. Driving smoothly will conserve grip, and make you a safer driver.
Brake soon, and gently
Be prepared to ease off the brakes (if you do not have ABS fitted) in order to steer more effectively. Locked wheels cannot steer!
Make the best use of ABS
If you do have ABS, you’ll be able to tell it has triggered by feeling a pulsing sensation through the brake pedal. If this has occurred do not ‘pump’ the brakes, rather keep a firm pressure on the pedal for maximum effectiveness. ABS is designed to help you steer as you’re slowing down so use this to your advantage and avoid obstacles.
Prevention is better than cure
Even if you do have ABS fitted, don’t get into the habit of using the system routinely, you’ll be able to slow down in a shorter distance if you use threshold braking techniques.
When attempting to pull out or while going up a slippery hill, use the highest gear possible. This technique applies less power to the drive wheels resulting in less potential of wheel spin. Don’t gun the motor! Once your wheels begin to spin, you are in trouble.
If you have good snow tires and chains, most hills can be negotiated. Coming down a slippery hill requires judicious use of the vehicle’s gears. A lower gear can slow your momentum. This is good because you do not have to use the brake as often and there will be less chance of locking the wheels.Caution must be used, however, as too low of a gear can cause too much back pressure in the engine, resulting in too much drag, which can also lock the drive wheels.
Many of the new automobiles have an ingenious safety feature called anti-lock brakes. These are designed to automatically pump the brakes to prevent wheel lock-up. Most vehicles on the road do not have this feature. If you do lose control, try pumping your brakes with short, repeated pumps instead of just pushing the pedal to the floor and holding it there.If this method fails and it seems you are destined to hit something, you may have a choice. A nice snowbank is better than ramming another car or sliding through a crowded intersection.
Winter driving is different from summer driving in other respects. Ruts may form in the snow and ice and cause problems. Once in the rut, it is difficult to steer out of it. In an attempt to steer out of a rut, you may be thrown out of control in another direction. High centering your vehicle can also result from ruts or snow build-up under your car.
Winter roadway width is usually narrower due to snow build-up. In this case, you do not have much margin for error in passing or meeting cars from the opposite direction.
Roads that are intermittently dry and icy pose very interesting and dangerous driving problems. This situation calls for extreme caution, reduced speeds and more distance between you and other drivers.
Winter driving has a detrimental effect on some drivers. It may make them more nervous, frustrated, tense and perhaps even aggressive. Some drivers, no matter what, will try to drive in winter as they do in summer. Thus, it is even more important to drive defensively and be extra alert to what is happening around you. Drive even further down the road than normal; this means, watch for the driver or the situation that is a wreck about to happen and allow enough stopping distance or maneuvering room.
A misconception, which must be cleared up, concerns stopping distances of 4X4 and front-wheel drive vehicles. Pulling power has absolutely nothing to do with stopping distance. Lock the wheels of a 4X4 on ice and you still have four
approximately 6″ X 8″ patches of rubber sliding down the highway. Many 4X4 and front-wheel drive owners are over-confident and that’s just plain dangerous.
Cruise control can become a killer on slick highways! With cruise control, the car either accelerates or decelerates to maintain a constant set speed. This works fine on dry pavement. However, on icy or snowpacked roads, the use of cruise control can cause accidents. The car may sense a need for increased power to maintain its set speed just as you enter an icy spot. This would have the same effect as if you suddenly stepped down on the accelerator. The result is almost always a break of traction of the drive wheels and a dangerous loss of control.
If you do get stuck (before you go into the survival mode) there are a few things you can try. Above all remember, DON’T OVER EXERT! It’s hard to keep your mind on getting unstuck while you are undergoing a heart attack.
First, clear a path in front and behind your wheels. Get the sandbag out of your automobile survival kit and spread sand or gravel on the path you have just cleared. If you forgot the sand, try a floormat under the wheel, branches cut with the ax in your survival kit or just about any other thing you can think of to put under the wheels to give traction.
Now try “rocking” yourself out. Accelerate forward until the car just begins to lose traction, then quickly move into reverse until the tires begin to break traction, then back the other way. You should gain a little ground each time and eventually break free. A good driver can master this technique with either a standard or automatic transmission; the trick here is timing between engine RPM and gear changes so you don’t rip the universal joint out.
Another idea is to gently accelerate with the emergency brake partially applied; this may prevent the drive wheels from losing traction quite as quickly.
Bridge surfaces freeze before roads do. Yeah, yeah, most people have heard that so much and have seen the signs so often that it no longer means anything. However, when traveling down the highway at 65 mph thinking how cool you look
passing everyone in the slow lane, and you hit one of these iced up bridges, it’ll mean something.