Driving in snow?

[TMND]

1 pedal works great on ice! Haven’t seen pavement since October in town here. Never once felt 1 pedal mode made me feel unsafe. This is the most rock solid, stable footed vehicle I’ve ever driven hands down (especially on snow and ice). Only ever used brake pedal when someone else slid into an intersection, stopped quickly in a straight line, felt good.

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[Maquis]

I think I've noticed that the rare few times we had snow last year, I'll be ready with foot to cover pedal when we get some actual snow this winter.

It happened to me in the rain. I was cornering and hit a pothole causing wheel-hop.

 

[Henry Ford]

My 2 cents: 1-pedal drive / stock tires was excellent in heavy snow on a recent trip through western NY. I didn't get any sense that the regen had any ABS character to it, but in my mind if you're needing ABS in the snow, you've generally made an oops and started stopping too late for the conditions anyway so maybe its there and i didnt cause it to activate. That said, the regen control was super smooth and gradual just like it is on dry pavement and so there wasn't an unexpected behavior.

In my experience, when the ABS kicks in, regen shuts off. It’s a bit unnerving because it feels like you’ve lost braking for a split second!

I agree with @Maquis. It's hard to say exactly what's happening with regen and ABS but it certainly feels like it's one system at a time.

Last month I had to drive to work before dawn. It had rained and snowed a bit overnight and the roads weren't treated. I tested braking action in my neighborhood (poor!), then again on the first 55 mph road I was on (really poor!). Snow gave way to black ice at intersections where other vehicles had been; braking action was nil! As I approached a light on a slight decline it turned red. No problem since I was creeping along. I released what little accelerator pedal I had inputted and the truck slowed down... until it didn't! ABS kicked in and I slid through the intersection in slow motion. There were two cars waiting but thankfully they saw what was happening to me. I honked my horn and gave the universal sign for I'm out of ideas . The truck maintained directional control through the ordeal.

Dedicated winter tires might have helped in my situation. I'm running stock ATs with about 12,000 miles on them. It doesn't snow much in Southeast Michigan anymore so I'll continue to take my chances with ATs at least until I need to replace them.

 

[SpaceEVDriver]

It's interesting that people are experiencing what feels like regen OR ABS, not both. I didn't get that feeling in the Mustang when I encountered ice. I haven't had the opportunity to play in the snow/ice yet with the Lightning. If we ever get any moisture here again, I'll go play in a parking lot to better understand the Lightning's behavior.

As I understand it, Ford's regen can be switched off by placing the vehicle in "neutral," so it doesn't fall under the requirement that regenerative braking be controlled by ABS:


49 CFR § 571.135:
S5.1.3 Regenerative braking system.

(a) For an EV equipped with RBS, the RBS is considered to be part of the service brake system if it is automatically activated by an application of the service brake control, if there is no means provided for the driver to disconnect or otherwise deactivate it, and if it is activated in all transmission positions, including neutral.

(b) For an EV that is equipped with both ABS and RBS that is part of the service brake system, the ABS must control the RBS.

 

[Maquis]

It's interesting that people are experiencing what feels like regen OR ABS, not both. I didn't get that feeling in the Mustang when I encountered ice. I haven't had the opportunity to play in the snow/ice yet with the Lightning. If we ever get any moisture here again, I'll go play in a parking lot to better understand the Lightning's behavior.

As I understand it, Ford's regen can be switched off by placing the vehicle in "neutral," so it doesn't fall under the requirement that regenerative braking be controlled by ABS:


49 CFR § 571.135:
S5.1.3 Regenerative braking system.

(a) For an EV equipped with RBS, the RBS is considered to be part of the service brake system if it is automatically activated by an application of the service brake control, if there is no means provided for the driver to disconnect or otherwise deactivate it, and if it is activated in all transmission positions, including neutral.

(b) For an EV that is equipped with both ABS and RBS that is part of the service brake system, the ABS must control the RBS.

That makes perfect sense. It’s just that when ABS takes control, there is a sensation of braking loss. The system is likely working as designed.

 

[Mmiketa]

I’m out in WV for a trip and leaving during a snow storm tomorrow morning. Sounds like it’ll be 5-10” coming down the mountain. We’ll see how she does. Wish I could have had a charger up here.

 

[Firn]

We are supposed to get a bunch of snow today, I'll grab the logger and see what happens!

 

[Runaway Tractor]

I noticed that for the first time this morning actually. Some rough pavement and small potholes triggered the ABS while slowing for a stop sign at the grocery store exit. For a split second, it felt like all braking ceased as it was transitioning from regen to ABS. That split second is easily noticed in the assometer and very startling the first time.

 

[Firn]

Testing Regenerative Braking in Snowy Conditions

I recently had the chance to test regenerative braking in a winter storm, monitoring brake line pressure with my OBD scanner. Here’s what I found:

Normal Mode

When I first left the garage (with warm tires), the roads were covered in dense snow. In normal mode:

Applying the brakes initiated regen as expected.

When I applied enough brakes to slide the tires, regen disengaged, and the mechanical brakes seamlessly took over, using ABS to prevent wheel slip.

Brake line pressure spiked when the ABS kicked in, and I didn’t notice any hesitation during the transition between systems.


One-Pedal Driving (1-PD)

Switching to 1-pedal driving introduced an interesting behavior:

Letting off the throttle caused mechanical brakes to engage early if the wheels slipped. Regen would drop, and the brakes would take over seamlessly, activating ABS.

This behavior surprised me since, in prior dry-road tests, 1-pedal driving did not use mechanical brakes. On snow, however, the transition between regen and mechanical braking was smooth and effective. Even though it was using mechanical brakes it "felt" like normal 1-pd driving.


Sport Mode

I also tested sport mode with and without 1-pedal driving:

Surprisingly, sport mode did not apply more regen in 2-pedal driving. The accelerator response was quicker, but braking performance felt the same as in normal mode.

The display indicated more regen was occurring, but I didn’t notice any increased deceleration compared to normal mode.


Second Test (After Ice Cream Stop)

On the way home (with colder tires), I repeated the tests and noticed a difference:

1-pedal driving struggled to engage mechanical brakes initially, likely due to lower tire temperatures and better traction. Eventually, on more slippery sections, it began using the mechanical brakes again, likely based on wheel slip sensing.

Sport mode now behaved as expected, with regen performance now feeling normal.


Conclusion
The seamless transition between regenerative and mechanical braking stood out the most in all modes. The system's ability to adapt to snowy conditions, especially in 1-pedal driving, was impressive.

I recorded my second round of tests if anyone wants to see the video (and hear my commentary). Let me know!

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