Everything you thought you knew about driving on snow was wrong
Jan 12, 2019 08:33AM
By Christopher Jensen of The New York Times - January 10, 2019
Ogden Nash described winter as “the season to be young, catching snowflakes on your tongue.” Sure, snow days are fun for children, but for drivers, wintry weather is a hazard.
The problem is that driver education classes typically gloss over what makes winter driving different and how to avoid and handle skids, said Tim O’Neil, the founder of Team O’Neil, a rally-driving school in Dalton, N.H., that also teaches winter driving.
That’s why even people who have been driving for decades can make crucial mistakes on snowy roads, said Mark Cox, the director of the Bridgestone Winter Driving School in Steamboat Springs, Colo.
“We see a lot of people from all over the country who have grown up in the Snow Belt and have years and years of driving experience and in reality have just been lucky because their technique leaves a lot to be desired,” Mr. Cox said.
The biggest problem is speed, and not knowing it will take much longer to stop, experts say. Here’s some other advice to avoid slip-sliding away.
Some snow is more slippery
The amount of grip available on snow can change sharply depending on the temperatures, said James H. Lever, a researcher at the Army’s Cold Regions Research and Engineering Laboratory in Hanover, N.H.
Warm snow is weaker and gives way more easily, so tires have a harder time getting a good grip, he said.
“As temperatures warm up, it gets more slippery. It is a big effect,” he said. For example, when the air is 30 degrees Fahrenheit, packed snow is about five times more slick than it is at zero degrees.
Researchers say when a tire begins to slide across the snow at higher temperatures it is more likely to melt the snow. That water then acts as a lubricant.
Smooth moves are important
On dry pavement, tires have so much grip that drivers can accelerate hard, slam on the brakes and make sudden, sharp turns, Mr. O’Neil said.
But that all changes on a slippery surface.
“We have less grip in the winter. One of the things you have to do in the winter is be way smoother,” Mr. O’Neil said. Otherwise, the tires can quickly lose what little grip they have.
On dry pavement it may be possible to brake while going through a turn. On snow it is safest to slow the vehicle first and then make the turn, he said.
“It’s sort of like walking on the ice. You take smaller, little tiny steps. You don’t try to run on the ice. It’s the same idea with a car,” he said.
Four-wheel drive isn’t a cure-all
“A lot of people overestimate the capabilities of their vehicles, especially people driving all-wheel drive. They mash the gas pedal and the thing goes forward with all four wheels pulling and they get a false sense of confidence,” Mr. Cox said.
“The beauty of all-wheel drive is to help get you moving from a complete stop, that is where it is the best — or climbing a steep hill. But when it comes to braking and cornering, all-wheel drive doesn’t give you much or any benefit. Often they are the first ones in the ditch.”
Be wary of all-season tires
All-season tires are a compromise, just like a houseboat, said Travis Hanson, the director of operations at Team O’Neil. “It’s not a good house, and it’s not a good boat,” he said.
For winter driving, the best winter tires are far superior to the best all-season tires, said Jennifer Stockburger, who conducts tire testing for Consumer Reports and is the director of operations at its auto test center.
One reason is a special tread design with “additional biting edges” called sipes, Ms. Stockburger said.
In addition, winter tires have a special rubber compound that stays more pliable — and thus grippy — when the temperature drops, she said.
One downside is that the softer compound doesn’t last as long as the compound on an all-season tire. Another is that the cornering and braking on dry pavement may be diminished.
“They are squirmier. The more pliable rubber. The additional cuts. There’s no free lunch,” she said.
The Quebec government considers winter tires to be such an advantage that in 2008 it began requiring them on passenger vehicles between December and March.
Those tires must have what’s known as an “alpine” symbol, an icon with a mountain and snowflake, on the sidewall indicating they meetinternational standards for winter performance. The law applies only to vehicles registered in Quebec.
Ms. Stockburger said anyone who drives in snow should have winter tires on all four wheels. “It is absolutely worth the investment.”
The electronic safety net
Most vehicles now have anti-lock brakes and electronic stability control.
Anti-lock brakes are designed to automatically pump the brakes and help the driver maintain control when trying to stop on a slippery surface.
Electronic stability control uses sensors to determine if the front or rear of the vehicle is going in a direction that’s at odds with where the steering wheel is aimed. Then, it applies one or more brakes to try to nudge the vehicle back in the right direction.
But drivers shouldn’t be using those regularly, Mr. Cox said.
“If your stability control or your anti-lock brakes turns on, that means you as a driver have made a mistake and the electronic nanny has stepped in to try to save you from that,” he said.
Instead, he said, drivers should view those as sensors. If the driver feels the anti-lock brakes or electronic stability systems engage, it’s a clear sign to slow down because the vehicle is approaching “the edge of available grip.”
And those systems work best with winter tires because they need traction to be most effective, Mr. O’Neil said.
What to do when it goes wrong
“When you do start losing control, you really need to look where you want to go rather than staring at whatever obstacle you might run into.” Usually, Mr. Hanson said, your hands will steer you in that direction.
And, hopefully, out of harm’s way.