Reading road key to winter travel
Bill Love
Correspondent
Even amid the winter season, when drivers should be used to it, many motorists are making basic errors. I’m convinced that this is partly due to drivers improperly “reading” the roadway surface conditions. I see many vehicles going too fast where they shouldn’t or too slow where it’s not necessary. The former often end up in the ditch – the latter block traffic flow and cause others to take risks
Actually, when this column is printed, I hope its message less relevant. Though today, as I I write, it’s very apropos – snowing at the moment, with a harsh forecast ahead. When I drove in from out-of-town last night, I saw five vehicle slide-offs – vehicles whose drivers, I suspect, misread the road surface.
Whether your vehicle is front-wheel drive, rear-wheel drive, 4WD, or all-wheel drive, stable highway driving is possible. Rear-drive cars are harder to get moving from a stop, and don’t scale grades well, but they are actually more stable at speed on slippery surfaces than front-drive vehicles. Front-drive cars lose lateral adhesion and steering when the drive wheels spin, but they do have superior traction for leaving a stop or climbing a hill. All-wheel and 4WD supply excellent “go power,” but can give a false sense of security for stopping and turning.
Whatever you drive, reading the conditions of the road you are on is a prerequisite for formulating driving tactics.
Dry Roads
Even dry roads have lower tire-adhesion levels during below-freezing temperatures. Additionally, the likely presence of sand or dust during winter reduces tire grip. It’s best to scrutinize the surface that your vehicle is about to roll upon at all times – seeing and steering around a pothole, for example, can be the difference between vehicle damage, an accident or no consequence whatever. Attempting a stop in the sand is difficult, whereas moving slightly to where the sand isn’t will make your stop uneventful.
Wet Roads
Obviously, wet roads are slicker than dry ones, and an appropriate speed drop is recommended. In winter, however, one must determine if roads are just wet, or if they are coated with “black ice.” Outside temperature indicators are among my favorite accessories in a passenger compartment. When they read “32,” it’s time to slow down.
If the vehicle I am in has no such device, I touch by brake pedal lightly (where no other vehicles are affected) to test for slickness. It is better to know the condition ahead of time, and slow down before a surprise skid takes place.
Remember, if you are using studded tires, your traction for turning and stopping on both dry and wet roads is inferior to all other tires. Everything goes well until an emergency unveils their inadequacy. Please allow extra following distances when driving on studs.
Slushy roads
This is the condition that evidently fooled the five drivers I saw in the ditch last night. Wet snow or slush has a propensity for grabbing tires, and pulling vehicles to the side. If you are on such a surface with other vehicles making tracks in the slush, it is best to stay in the tracks. Moving out of them can cause even heavy vehicles to be pulled from side to side and lose control.
Snowy Roads
Snow is easy to see, but adhesion levels vary greatly according to conditions. For instance, snow generally affords better grip at 20 degrees than at 32 degrees. When the surface is packed, it’s much harder to get traction that when it’s loose. If there is not a lot of snow, better grip can often be had by moving slightly out of the tracks, where some loose snow exists. When the snow is deep however, moving out of the tracks into too-deep snow can pull your vehicle aside as slush does.
Glare Ice
Often, we get a thin coat of black ice, as described above. That is bad enough, but other times, due to freezing rain or melted and refrozen packed snow, we encounter glare ice. This is the kind of surface they play hockey on – barely suited for vehicle travel. The best thing to do on a roadway like this is to get off as soon as possible. On true glare ice, vehicle speeds of 25 mph are hard to safely achieve. Even within categories, grip will vary. Depending on makeup and ambient temperatures, some snow and ice is slicker than other snow and ice. Winter driving experience is the only route to total confidence and proficiency.
In any of these conditions, except dry roads, reducing speed is the best defense. Know your vehicle, its tires, and its overall handling characteristics. Don’t drive overly slow – “low” doesn’t necessarily equate to “safe,” especially as it affects other drivers. On a straight highway, with packed snow, at 20 degrees, for example, driving 50 mph may be perfectly safe. The keys are maintaining proper following distance, and keeping a sharp eye for changing road surface conditions.
Additionally, avoid sudden steering movements or brake applications. Smooth, gradual steering and braking work much better, so don’t overcorrect excessively in the event of a skid.
Please read the road well, and stay calm.
Also pray for an early spring.
Readers may write to Bill Love, c/o The Spokesman-Review Auto Section,P.O. Box 2160, Spokane, WA 99210. Or you may contact him via e-mail atprecisiondriving@spokesman.com.
