Careening down the road in an uncontrolled skid can be a terrifying experience. In this month's Focus on Safety column we'll take a look at the causes of this common driving mishap. We'll also discuss ways to correct a skid and avoid serious injury to yourself, the occupants of the vehicle, and the car itself.
Because of our limited space here, we'll focus on the most common skid drivers encounter — the "oversteer" skid. This is when the back end of the car swerves out, seemingly pulling the rest of the vehicle with it. Be advised that most of the tips here, used properly, will help remedy any skid situation.
When we discuss skidding, what we're really talking about is friction. How well does the vehicle hold the road? Traction — the tendency of a car to "stick" to the roadway — has a direct relation to whether it will skid or not.
The following factors contribute to vehicle traction and the likelihood that a car will go into a skid: road surface, vehicle velocity, road conditions, weather, lighting, tire wear, tire inflation, temperature, type of vehicle, suspension system, and vehicle load, among others.
This is quite a laundry list of influences. We'll narrow it down and take a look at several of the most critical issues affecting vehicle control. Then we'll talk about the corrective actions you, as a driver, can take to pull out of a skid.
Road Surface: The single most important factor affecting the potential for a car to skid is the condition of the roadway. Is it asphalt or concrete? Rough or smooth? Think of sandpaper. It has different grades of roughness. The coarser the sandpaper, the more friction it presents to the surface being sanded — i.e., the faster it "takes down" that surface. This is similar to a car's ability to hold onto the road. It becomes even more critical when coupled with our second factor, road conditions.
Road Conditions: This is not the same thing as road surface. For instance, when you have a rough road surface covered with ice, the tires may never actually "see" the roughness beneath. As we've discussed in our braking story, different road conditions present varying friction opportunities to the tires. A coarse roadway in the rain will hold less firmly than that same highway bone dry; likewise, snow-covered pavement will present even fewer friction possibilities to the tires. As in braking, the forces working upon a vehicle become focused at the point of contact — literally, where the rubber meets the road. Throw an ice storm or two in there, and the friction coefficient can approach zero. So, what are the conditions of the road? Is it raining? Snowing? Was there an overnight freeze? All of these conditions influence, separately or together, the tendency of a vehicle to skid.
Speed and Direction of Vehicle: How fast is the vehicle going and where is it headed? As Steven Stoltenberg of Greg Manning Associates told us (GMA does accident reconstruction scenarios for corporate clients), "Energy increases as a square of the velocity." So the faster you go, the more energy the vehicle must dissipate before it comes to a stop. In what direction is the vehicle traveling? If the road is heading east and your car is going north, you have a problem.
Condition of Tires: This includes tread wear, tire inflation, and tire temperature. How much "meat" is on the tire? A new tire with lots of tread will grip the roadway much more effectively than a bald tire. How much air does the tire have in it? A deflated tire has too much play in it and will not react properly to changing road conditions; conversely, an over-inflated tire will tend to "skim" across the pavement. Lastly, how hot are the tires? An overheated tire will soften and lose gripping power.
Steering Input: Once a skid has commenced, where are the tires pointed? How does the driver respond to the skid? Every expert we talked to indicated that novice drivers overreact to skidding, turning the wheel too far in the opposite direction and exacerbating the problem.
These are the main factors which influence skidding. Of course, ideally you'll take note of these conditions ahead of time and avoid skidding. But let's assume you've done everything right and still find yourself in a skid. You come around a turn on some lovely mountain spring day and hit a patch of ice. Your car goes sideways. What now?
We posed this question to several experts in the field — Danny McKeever of Fast Lane Driving School in Rosamond, California, and Randy Bleicher from Bob Bondurant School of High Performance Driving in Phoenix, Arizona. Their answers were remarkably similar.
1. Look where you want to go, and not at what you might run into.
One big mistake novice drivers make is to focus on obstacles. They see a tree up ahead and think, "I'm going to hit it!" (Randy at Bondurant calls this the OS syndrome, as in "Oh S__t!") Unfortunately, the human body has an invisible connection with the mind. When the mind focuses on something, the body follows. Don't do that. Instead, direct your attention to the open space next to the tree. The body — and car — will follow.
2. Point your front tires where you want to go.
Or, as you may have heard, steer in the direction of the skid. And don't overcompensate. Simply put: look where you want to go and then point the tires in that direction. The car will follow suit.
3. Apply throttle.
Weren't expecting this one, were you? The idea here is to balance the weight of the vehicle over all four wheels, increasing traction. By giving 10-15 percent throttle, the vehicle gains contact with the ground. As Randy at Bondurant says, "Weight transfer is everything."
4. Wait to feel the pause.
Once the preceding step has been accomplished, there will be a slight pause as the vehicle rights itself, stabilizes, and gains control. Again, Randy of Bondurant: "The pause is a transition period." You're now ready for the final step.
5. The pause tells you it's time to steer.
In a reprise of Step Two, it's time to fine-tune your steering input and once again point your front tires in the direction you want to go. If you've done all the preceding steps correctly, you should come out of the skid unscathed.
There are several other issues we haven't addressed in this article. For instance, what about ABS? Anti-lock braking systems allow the tires to continue rotating in low-friction situations. In a severe skid, such as on black ice, stomping on the brakes and holding them can take the place of applying throttle (Step Three). However, because ABS is a largely misunderstand and misused technology, we suggest following the steps above as listed.
We'd like to thank our experts for their assistance in assembling this article. We've included their contact information below, in the event that you'd like to get in touch with them in regards to their services.
Greg Manning Associates
1061 "A" Turkey Point
Edgewater, MD 21037
Fast Lane Racing School
P.O. Box 2315
Rosamond, CA 93560
The Bob Bondurant School of High Performance Racing
P.O. Box 51980
Phoenix, AZ 85076-1980