My SUV has adaptive cruise control and lane-keeping assist. I was using both while driving on the highway with my teenage daughter and she said her driving instructor told her never to use them in the winter. That surprised me because I thought they were safety features. Is the instructor right? What’s the problem? – Laurie, Kingston, Ont.
On slick winter roads, driver-assistance technologies don’t always make for a safer drive.
“These features can sometimes react in ways that reduce driver control,” said Carl Nadeau, a driving expert with Michelin and a former racecar driver. “For example, adaptive cruise control may apply the throttle unexpectedly when climbing a hill, which can cause the wheels to spin on icy surfaces.”
Advanced driver assist systems, including adaptive cruise control and lane-keeping assist, are designed to sometimes take control on dry roads to keep you out of a collision, he said.
But on slippery roads, they could help too much – and at the wrong time, Nadeau said.
Similar to conventional cruise control, adaptive cruise adjusts the throttle to keep you at a set speed, but most systems can also apply the brakes to keep you at a set distance from the car in front.
Many owners’ manuals say to avoid cruise control of any kind on slippery roads.
For instance, the manual for the 2026 Subaru Crosstrek’s driver assistance system states that you shouldn’t use adaptive cruise control on “frozen roads, snow-covered roads or other slippery road surfaces [because] the tires may spin, causing loss of control of the vehicle.”
If you’re turning the wheel while adaptive cruise control slows the car, for instance, the tires could lose grip.
And if your foot is off the gas pedal when you’re using cruise control, you might not feel it when the car starts to slide, he said.
Lane-keeping assist, which steers you into the middle of your lane if you drift toward the sides, could also steer you into a skid if you are braking or accelerating while it’s turning, Nadeau said.
“[It] can also try to steer the vehicle through tire tracks in the snow, which may be uneven and destabilize the car,” he said.
That’s especially true with earlier systems, where the help was especially abrupt.
Giving up control?
Also, if you’re counting on those features to keep you on your lane or from ploughing into the car in front of you, they might suddenly stop working, Nadeau said.
“In snowy or icy conditions, these systems often can’t read lane markings or maintain accurate distance, so many vehicles will automatically disable them," he said. “When that happens, you’ll typically see a warning light or message on the dashboard.”
But the bigger issue, experts say, is what happens when you give up control in the first place.
“Every vehicle will always react better to smooth controls rather than rough commands,” said Ian Law, a former racecar driver and chief instructor at ILR Car Control School in Minden, Ont.
You can avoid most winter skids by paying attention to the road and steering, braking and accelerating smoothly – not by relying on systems that can intervene abruptly, Nadeau said.
Plus, some drivers don’t focus on the road while using these systems and assume they will spot problems for them. But no car sold in Canada is designed to ever fully drive for you. You need to watch the road and be ready to take over.
“Driving isn’t so much a job – it’s a responsibility,” Nadeau said.
Added stability
But modern vehicles also have safety technology that could keep you out of a winter crash, Nadeau said.
“Core safety systems like anti-lock brakes [ABS], traction control [TCS], and electronic stability control [ESC] are extremely valuable in winter driving,” he said. “Traction control helps limit wheel spin during acceleration, while stability control works to prevent skids by selectively applying brakes and managing engine power to keep the vehicle stable.”
While most cars let you turn off traction and stability control – which you might do, for instance, if you’re stuck in deep snow or if you’re off-roading – you should always keep them on for normal driving, he said.
While those systems still kick in if you start to slide while using cruise control or lane-keeping assist, it’s better not to give up control in the first place.
“It’s far, far easier to prevent a skid than to correct one,” Law said.
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