Sunday, December 21, 2008

Snow Rules Driving

Although we are experiencing frigid temperatures in the mid 60's here in sunny Southern California, some of you out there are in the midst of actual winter. As I remember winter quite fondly and am very jealous I thought I would share a few tips for the road in these difficult conditions.

Driving in snow and ice can be a very frightening proposition particularly if you haven't done it before. But there are many things you can do to ready yourself and to make your winter driving experience safe and maybe even fun.

1. Slow Down: It seems like such and obvious point but it's often the point people forget first. One thing that people tend not to realize is that it is much easier to work your way up to an unsafe speed than it is to come back down from said speed. The reason is that if you are prudently applying force to the drive wheels of the car they will maintain some grip on the road as they are spinning. Stopped wheels, on the other hand do not continually work to hold the road.

2. It takes very little force to move a car in the wrong direction: Several years ago we had an ice storm at my parent's house. The neighbor up the hill (an experienced winter driver) pulled his car out of the garage and into the driveway to warm it up and wait for his wife so that they could drive to work together. Sitting in the driveway in park reading the newspaper he realized he felt the strange sensation of movement. When he pulled the paper down to look outside he realized that a slight cross breeze was pushing his 3500lb car sideways. Before he could react his car was pushed over an embankment and flipped over into his front yard. While parked he managed to flip and total his car. I tell this story to illustrate a point, that driving your car is all about applying force to make changes. Turn the wheel and the momentum of your car is creating force one way while the wheels are translating force in a different direction to cause you to turn. On slippery ground often the slightest force can put you into a troubling slide.

3. Know your car: Do you have front wheel drive or rear wheel drive? Do you have all wheel drive, perhaps four wheel drive? is your car heavier in the front or in the back? What kind of tires do you have and how to they work on ice? Do you have anti-lock brakes or not? All these things and more will drastically effect the way your car handles on slick surfaces. If you haven't driven in these conditions you should get yourself to a large empty parking lot and practice. Learn how your car stops and turns at different speeds. Practice safe braking techniques and learn how to control a slide.

4. Braking: Experts suggest you should at least double the amount of space you give yourself to stop or re-act. Under normal conditions you should leave yourself two car lengths for every 10 miles an hour. For ice make it at least four car lengths. When applying the brakes it's important to know if you have abs. Anti-lock brake systems respond to slippery conditions by stuttering the brake pressure at a high rate of speed. This allows the wheels to continue turning which helps maintain grip on the road, while slowing the vehicle down. If you do not have abs you should practice pumping your brakes in order to get the same effect. Pumping the brakes allows the wheels to slow while still moving and maintaining some level of control. But remember pumping the brakes when you do have abs will only disable the abs. Resist all urges to panic and lock up your brakes this will most certainly cause you to lose all control. An important note for those of us with SUV's four wheel drive is not four wheel stop. Four wheel drive will increase the mobility of your vehicle but once you take your foot off the gas and start to apply the brakes you are back in a regular car again.

5. Turning: In ice and snow turning is a tricky proposition and I will first remind you of rule 1... slow down. The important thing in a turn under these conditions is to maintain the movement of your wheels. This means slow down before the turn and then take your foot off the brake and apply some pressure to the gas on your way through the turn. With front wheel drive this is relatively simple as the front wheels are pulling the car through the turn. With a rear wheel drive vehicle this as with many other parts of ice driving, is more complicated. If you add too much gas to the rear wheels you can fishtail, over-steer, or simply push hard enough to break the turn wheels' grip on the road causing a slide. Prudence is a virtue here. If you have four wheel drive or awd this is where things are the best for you, in a slippery turn you should see driving force on all four wheels helping maintain stability through turns.

6. The Slide: The slide is the thing that keeps many a driver in the house next to the fire with hot cocoa in this kind of weather. When you begin to slide almost universally your instincts are wrong. The first thing you must concentrate on once the vehicle has lost traction and is sliding is returning control of the vehicle. Many many people have gotten in trouble with the instinctive reaction to try and stop everything. The brakes are not your friend in a slide. Experts say you should steer into a slide and apply some gas to re-establish grip with your tires, then steer your way to safety. This is where that parking lot practice session will be invaluable, learning how much gas is the right amount to maintain grip and how much is too much makes all the difference.

7. Smooth Moves: One overall piece of advice throughout your winter driving experience is that all of your moves should be smooth and steady. Panic reactions are learned in your countless hours of dry, safe conditions and simply do not work on ice. The brakes are a useful tool but more often than not they will get you into trouble.

8. Be Prepared: After the first snow you will find (as some friends of mine recently did) that snow chains and traction tires are out of stock quickly. If you live or travel in wintry areas buy a full set of chains and learn how to use them. You may not ever find yourself in a position to need them but boy are they a lifesaver if you do. And again practice, practice, practice.

9. Pay Attention: Maybe this should be rule 1.

Driving in bad weather can be very stressful but a few simple things will help to make it a safe and enjoyable part of your year.


Mike said...

Good advise, generally!
In #4, if you have four wheel drive, compression, is a big help, in slowing the vehicle. Downshift. and let all 4 wheels do the slowing. Braking puts almost all of the effort on the front wheels, causing them to lose traction, easily. This is a problem, because you not only can't stop, YOU CAN'T STEER!
If you lose control, and start to spin, TAKE YOUR FOOT OFF THE BRAKE, and let go of the steering wheel. The vehicle will straighten out.
One more thing. Driving on ice/hard pack snow, is just like driving on dry pavement--At 100+mph.

Mike said...

Almost forgot--For God's sake leave the cruise control OFF!