Why Rear-Drive EVs Can Get Sketchy on Ice—and How to Remedy the Problem

• All electric vehicles use regenerative braking to slow the vehicle using one or more of its electric motors.
• However, with rear-drive EVs, which is the typical layout for entry-level models, that braking can have a destabilizing effect in slippery conditions and induce a slide.
• Make sure to switch off the regenerative braking function before heading out on slick roads.

It feels like it has already snowed umpteen times this winter at our Ann Arbor, Michigan, headquarters and, after a particularly slippery couple of days, a bunch of our staff was sharing notes on the same topic: rear-wheel-drive EVs whose regenerative braking was initiating slides.

Rear-wheel drive has made a comeback among electric vehicles and is the norm for models at the low end of a model range—including Tesla, Porsche, Hyundai, Volvo, Lucid, Volkswagen, and others—with a single electric motor located over the rear axle. These models are not only less expensive, but also are often more efficient with additional range. Now, before you jump to the conclusion that no one should be driving a rear-drive vehicle—EV, gas-powered, or otherwise—who lives in a place that sees snow, we heartily disagree. Fitted with a set of high-quality winter tires, we've had no issue getting through Michigan winters in all manner of rear-drive vehicles, and we prefer the lighter weight and often truer handling that tends to come along with rear drive versus all-wheel drive.

Also, this winter, plenty of folks who live in areas of the country with traditionally mild winters have found themselves unexpectedly driving in snow.

Here's the issue: Lifting off the accelerator in an EV applies regenerative braking, where the car uses the electric motor or motors to slow the vehicle, recouping energy along the way. It's become commonplace to drive an EV using only the right pedal, with no need to hit the brakes in routine driving. But when the only motor is powering the rear axle, and the available grip is ultra-low, a gentle initial nudge from the regen braking can overwhelm the rear tires.

Even though the vehicle's controls immediately react to this excessive tire slip and shut off the regen, the slide is already instigated, and the stability control can only make the most of the available traction but can't create more. No one spun, but this led to more oversteer than almost any driver would be comfortable with. Sure, sliding around in an open area this can be fun, but it's a different story when white-knuckling the morning commute at 20 mph on icy two-lane roads with oncoming traffic.

Essentially, it's the same effect as lightly grabbing and releasing the parking brake, which has long been a method to instigate a slide. And this induced oversteer is more dramatic on vehicles with tires that aren't optimized for icy conditions. For example, a rear-drive Volvo EX30 that was wearing its stock all-season tires was the worst offender. But it at least had new, full-tread-depth tires; an EV on bald tires would be dramatically worse. However, our long-term Lucid Air Pure wearing dedicated winter rubber wasn't immune, generating some rear-end slides that were unsettling to both our drivers and probably to drivers in surrounding traffic who might have witnessed it.

We got a chance to investigate this issue further at a winter proving ground recently with Lucid engineers. On snow, this rear-end regen effect was a non-issue, as there is sufficient traction, but performing a simulated lane-change maneuver on glare ice caused an amount of sideways that would frighten most any driver. Once the slight bit of initial regen starts to break traction, the system reacts immediately to switch off the regen but there's simply no way to quickly correct it because there's just no grip.

On the other hand, in an all-wheel-drive EV, both axles apply regen simultaneously. That also can exceed the available traction in slippery conditions, but it doesn't induce a tail-first slide like braking the rear axle does. Plus, dual-motor vehicles can vary the torque going to either axle to better get itself back in line.

The fix is to make sure you switch off regenerative braking—or turn it to its lowest setting if there's no way to fully shut it off—before you head out in slippery conditions. When we did the same maneuver on ice after making that change, it completely fixed the issue, with no destabilizing effect to the vehicle.

This issue isn't a surprise to the automakers; in fact, the owner's manuals for many vehicles—including the Tesla Model Y, Lucid Air, and Volvo EX30—specifically recommend using a lower regenerative-braking setting in snowy and icy conditions. But we'd bet there are a whole lot of EV drivers, including some who work at this publication, who haven't read and heeded that advice.

Dave VanderWerp

Director, Vehicle Testing

Dave VanderWerp has spent more than 20 years in the automotive industry, in varied roles from engineering to product consulting, and now leading Car and Driver's vehicle-testing efforts. Dave got his very lucky start at C/D by happening to submit an unsolicited resume at just the right time to land a part-time road warrior job when he was a student at the University of Michigan, where he immediately became enthralled with the world of automotive journalism.