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Comment by peeters | Hacker News Reader

How fast does the regenerative braking start? When I drive in an ICE with two pedals, when driving in an area with hazards, kids, etc, I frequently will take my foot off of the gas and hover it over the brake so that I'm able to respond quickly. I can do this because taking my foot off the gas while maintaining speed doesn't make an abrupt impact if I'm maintaining speed in a flat area.

I would still want to be able to respond equally quickly in an EV, but it seems like it would lurch quite a bit if I did the same in a one-pedal setup?

I don't know that I'd want a full toggle in an inaccessible spot to be able to coast. Do any EVs have like a paddle to coast/disable regenerative braking?

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Do you have two feet?

Left-foot braking is unpopular outside of racing but only takes about a day to get used to. For the use case you're describing it's probably even less since you'd probably only use it if you need maximum braking in an emergency.

The real challenge is what happens when you have to react instinctively in an emergency. That's going to take more than a day.

I would recommend people who want it in their toolkit left-foot brake exclusively for a week and do it semi-regularly afterward. It took a day for it to stop feeling weird for me.

In a one-pedal setup if you jerk your foot off the pedal it'll immediately start slowing down significantly. In the majority of situations you will react significantly faster with one-pedal driving than without. The only exception is if you're hovering over the brake pedal. Not my style, but to each their own.

Sure, you react faster. With the wrong reaction in an emergency.

In a traditional (automatic, anyway) car, there is one way to brake. You brake lightly if you want to brake lightly, and you brake harder to stop faster.

In a one-pedal EV, you lighten up on the accelerator to slow down a bit, and you remove your foot entirely and put it somewhere else to stop faster.

I would love to see NTSB or a similar group do actual simulator studies to see how normal people react.

In my EV in single pedal taking my foot off the accelerator is already instantly like having heavy braking. By the time I'm touching the brake pedal even slightly it is like I'm stomping hard. Coupled with collision detection priming the brakes potentially before my mind registers the potential collision I'm not worried about not being able to hover over the brake like in my old car.

I think you should be worried. Taking your foot off is heavy in the sense that it slows you down at decent speed. It is not heavy in the sense of an emergency stop, nor is having your foot on the pedal ready to remove priming you to slam on the actual brakes.

I’ve never heard of collision detection priming the accelerator to apply the mechanical brakes when a foot is removed.

You've never heard of collision detection priming the accelerator because it primes the brakes not the accelerator when it detects a potential collision. Its unrelated to me lifting my foot.

And I've definitely experienced it happen. I've lightly touched the brake pedal with AEB warnings going off and it really slammed on the brakes.

Either way I imagine neither of us has any hard numbers to actually back up either driving style. I'm just pointing out there's no lag to regen braking and in many cars it can be pretty heavy braking.

My point is that, if a driver gets used to heavy-ish braking from the accelerator pedal, they might not tap the brake pedal on time in an emergency.

If you're relying on saving the time to take your foot from the gas to the brake in order to save the life of a child or your own life, then you should probably just slow down.

You're making a lot of assumptions about me and flipping them into a big false dichotomy.

It's actually entirely possible to both drive at a safe speed and even still want to be able to brake quickly when you see potential hazards on the road.

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