Scott Sturgis' Driver's Seat: Lessons learned from winter driving

Now that the spring equinox is almost here, it’s a good time to review what we’ve learned from driving during the winter of 2014-15. It was a winter to remember. So like the good students we all hope to be, let's review the material, and clip and save it for the future. Then pull this column back out when the snow makes an unwelcome return appearance … next year. Lesson 1: People are driving too fast in bad weather. In good weather, I am a motivated driver. But when the snow starts falling, I find the recommended 45 mph on most Pennsylvania limited-access highways is usually far too high. The numbers bear it out. A total of 17,832 crashes involving ice or snow/slush covered roadways were reported in Pennsylvania during the winter of 2013-14, according to data provided by the Pennsylvania Department of Transportation. Massive pileups in Michigan, Pennsylvania and New Hampshire this year should remind us to be alert for possible bad weather when temperatures are low. In the New Hampshire crash on Jan. 2, Manchester District Fire Chief Al Poulin told WCVB in Boston that there were many vehicles on the road driving in excess of the 75 mph speed limit. Lesson 2: All-wheel drive is a good thing. I’ve long been a fan of front-wheel drive. I thought it was good enough. But this year, I managed to get a schedule of all-wheel-drive vehicles during the perfect storm of events, and I learned how wonderful it could be. Dan Edmunds, director of Vehicle Testing for Edmunds.com, agrees. “Some of the vehicles I’ve tested — it’s amazing how well they’ll accelerate on snow compared to a two-wheel-drive version, even with front drive,” he said. For the snowluge of 2014-15, I enjoyed an all-wheel-drive Honda Pilot, Mazda CX-9, Nissan Murano, and — most surprisingly — a BMW 2 Series XDrive vehicles. That low-slung sports coupe turned out to be an unlikely hero. I drove it in a surprise storm on an inch of icy snow, and using Sport+ mode for extra traction control, it never slipped once. Then I grew especially daring, climbing a neighbor's ice-covered driveway that my son was afraid to walk down. Once more, not a slip was to be had. How could this be? Don Remboski, vice president for innovation research and development at Dana Holding Corp. in Maumee, Ohio, has given this a great deal of thought in his role at the automotive engineered driveline supplier. He explained that engineers consider each tire a “contact patch,” where the rubber literally meets the road. All-wheel drive gets all four contact patches working together, in theory, but because each tire may be on a different surface (ice, dry pavement, snow) the tires won’t distribute the power uniformly. Old-time four-wheel-drive systems allow each side of the vehicle to work independently — a setup known as the limited-slip differential. All-wheel drive allows each wheel to operate independently, and seamlessly, without any input from the driver. Sensors at each wheel are tiny cogs measuring the revolutions of each tire. They transmit the information to the car’s computer, which redistributes power when it recognizes one wheel moving much faster than others — or reacting to other combinations of movement as needed. Most systems apply some brake pressure to slow the spinning wheel, although more complicated systems will use overdrive or clutches to produce the same effect, Mr. Remboski said. Traction control also functions in a similar manner. Another big improvement for winter traction has been in tires, Mr. Remboski said. Today’s winter tires — which could really be called “snow-and-ice” tires rather than just snow tires — have better formulated rubber compounds for those surfaces. Lesson 3: Laws of physics still apply. I hope to ferociously combat that other winter driving animal, the Overconfident SUV Driver. Everyone has seen that driver morph into SUV Driver in the Ditch — and both Mr. Remboski and Mr. Edmunds mentioned that stereotype without being prompted. All-wheel drive and traction control are excellent assistive devices designed for getting the vehicle moving. No matter how wonderfully they work, though, they still all stop in about the same distance on snow and ice, Mr. Remboski said. “It's easy for someone to fall into a false sense of security — it pays to be extra cautious with attempting to stop,” he said. Mr. Edmunds agreed. He noted that his own daughter is learning to drive and he has some reservations about an all-wheel-drive vehicle for a new driver. “Part of me thinks I'd almost rather have her in a two-wheel-drive car when she's learning just to have her aware of how little traction there is in certain conditions,” Mr. Edmunds said. A final illustration of this: The BMW 2 Series that climbed the icy driveway early in this column didn't come back down without causing me — and the car — to create some skid marks. But we both made it down without incident.