I have a theory that one-pedal driving also improves traffic conditions by reducing the over correction inherent to two pedals. In traffic we hit the accelerator when space opens up in front of us, then switch quickly to brakes when the brake lights in front go on. The switch lessens our ability for fine control and it's exacerbated by the inertia of deceleration, so we almost always over correct. This has a cumulative effect in following cars.
One pedal driving allows us fine motor control without a drastic switch. The regenerative braking also encourages us to not over-brake (you grow to love the idea that you are recapturing energy and avoiding wear on the pads).
> reducing the over correction inherent to two pedals.
Leaving space in fronto of you and trying to keep a constant speed also reduces this effect, this is ironically most used in 3-pedal driving as otherwise you’ll need to go into first gear when hitting a complete stop.
> Leaving space in fronto of you and trying to keep a constant speed also reduces this effect
I would like to see some sources on that claim. Or some reasoning.
The thing is I live in one of the cities with the longest commute distances and I’ve spent a lot of time in stop and go traffic thinking about this exact thing. I used to think as you do. I would focus on a truck in the traffic far ahead of me and try to use it to maintain a constant speed at the average of the highway speed. in my experience it creates this laggy elastic effect that probably doesn’t help.
Recently I heard that you should try to maintain an equal distance between the car in front of you and the one behind you, and I think this actually works better (obviously this is my anecdotal experience)
It starts to work when there are a few others doing it too. All of the sudden, it’s like magic, traffic is suddenly moving and there so no annoying stopping and going.
There are for sure studies on this. I remember seeing one from Seattle specifically, but others as well.
Speeding up and slowing down causes an accordian effect that results in slower speeds for everyone. The time it takes to reduce speed or stop, then recover to a higher speed is higher than just cruising at a middle speed.
I drive a manual and I never hurry in my commute, at rush hour or when there’s some accident on the highway people get crazy, they look like ants on a kicked nest, i just try to drive at a constant speed, and most of the time it takes me almost the same time, compared with a reference vehicle, to get out of that craziness without any stress.
I agree with that. Save gas / energy as well. People accelerate, pass me, then slam on the brakes at the red light, where I catch up with them. Or the traffic is really packed in all lanes, but still moving. They accelerate, start tailgating the person in front, and then inevitably having to slam on their brakes.
The one pedal driving can be used with an IC car too in certain conditions, just leaving more room ahead.
One data point I've noticed is that when a line of cars is at a stop light on a downward hill - when the light turns green, the traffic starts moving quicker than on the same scenario on flat land or uphill.
When getting off the brake the cars are already rolling a little bit before the move to the accelerator pedal and the effect is compounding.
Regen also means cruise control works as it should, so no speeding tickets when you are going down a steep hill (and where the police aways seem to sit)
Don’t most modern cars, even ICE cars, both slow-down-to and speed-up-to the speed designated by cruise control? I know my Subaru does, and my old Audi did, and both of the two Ford Escapes I drive for work do.
My wife's 2015 Honda CRV will allow the car to exceed the cruise control's set speed by up to 5 mph before the CVT raises the engine speed to apply engine braking.
In my 2016 Subaru BRZ (manual transmission), cruise control would never apply brakes, so if the hill was steep enough that engine breaking was slowing the car, then it could potentially exceed the cruise speed. But it would need a nearly 10% grade to do that in 6th gear at 60 mph.
Anecdotally it seems like it decreases my reaction time in emergency braking situations as well. Had a cat run out in front of me, and in the time it took my foot to start hitting the brake I was already slowed enough to have avoided hitting it.
It also smooths traffic flow because people are no longer slamming on their brakes, possibly in reaction to brake lights in front of them; instead they're keeping more distance and driving more predictably (down hills, to stoplights)
There's a great video from "Technology Connections" covering one-pedal driving here [1]. The gist of it is that one-pedal breaking doesn't have a great way to control the break lights, making it difficult for the cars behind you to recognize that you're slowing down, which can cause accidents.
This is only a problem in some EVs. Teslas, for example, illuminate the brake lights correctly when regenerative braking is used. The pinned comment on the video also suggests Hyundai may have fixed this on their cars by now, although I don't know whether they followed through.
IIRC the industry went from hard regen "may illuminate" -> "shall not illuminate" -> "must illuminate". Some cars designed and/or type approved when the middle one was regulatorily current follows it.
Manual transmissions (and sport shifting automatics) of most cars from 1904-2024 of sports coupes to trucks don't illuminate the brake lights when engine braking. Drivers following cars should be basing most decisions based on relative speed based on these existing.
If you were to follow behind me in my 2004 manual sports car or a 2021 automatic and only applied brakes when I did, you'd be speeding in my neighborhood and rear ending me, as I keep both in second gear and it keeps me at 20mph.
Having no brake lights for regenerative braking sounds incredibly dangerous. Regenerative braking can slow the vehicle down quite quickly, and as the name "one-pedal driving" suggests, it's common to barely touch the brake pedal at all.
Perhaps a better version of your complaint is that Tesla has made the threshold for the brake lights too sensitive; but I would be curious how much observation went into drawing that conclusion.
I drive my manual and auto cars like this, downshifting instead of using the brakes and preventing dangerous acceleration. I often only use the brakes from 20mph and below (though may touch them during a downshift)
Thinking it's more dangerous is odd as it's a great example of fail safe.
Wasn't his whole problem with one particular implementation of one-pedal driving, the Ioniq 5? As I recall, it was poorly implemented and had a relatively common use case that would allow you to stop without the brake lights ever coming on.
This isn't really a problem that other EVs have had. The brake lights come on when you slow down, just as if you had used the brake pedal. It's mostly as easy as triggering at a certain amount of kW generated.
> Wasn't his whole problem with one particular implementation of one-pedal driving, the Ioniq 5?
Yes. I watched that Tech Connections video a while back. In that implementation, his car would slow down too quickly without brake lights. I think it would get down to something like 15 mph from 55 before they'd come on, yet the deceleration was at least as rapid as casual braking.
I agree with the Tech Connections example; I have no comment on other EVs.
I can go from 75 to 5 mph in my ICE with the brake lights never coming on. Or, I can maintain 75 mph with my brake lights on 100% of the time.
But really, there should just be a standard - it seems obvious and easy for EVs to get it right: If deceleration is > X m/s^2, then brake lights are on.
The European Union has a regulation that requires EVs to illuminate their brake lights anytime the regenerative-braking system’s deceleration rate exceeds 1.3 meters per second squared, or about 0.13 g.
Simply because I've been driving TVs for a while and "in the beginning" when there was no rules for brake lights to be turned on when regenerative breaking, I got into trouble (German highways) with cars driving behind me and not being able to anticipate / react fast enough when I used it.
I quickly learned to force the break lights and started to follow this issue closely. That's how I became aware of the number.
How the EU saddled for 1.3 and not 1.2 or 1.4 is beyond my knowledge.
Unless I downshift using paddles, my ICE will coast forever from 75. My PHEV, on the other hand, will slow down much faster. I want my PHEV to illuminate the brake lights if I'm decelerating above a certain rate, just as you suggest.
It never occurred to me that I might want my ICE to do the same, but I suppose it would be helpful if I'm heading downhill and downshift without touching the brake.
How will we then be able to tell which drivers are ignorantly riding their brakes all the way down a long hill, versus the drivers using engine braking?
>Brake lights.....will remain on when the vehicle fully stops.
Mmmm, nothing better than a dark, rainy evening in November in a city after a long day at work and you're stuck for minutes on end right behind a car with red lights burning into your retinas.
Wankers.
I'm a bit surprised to read that one-pedal driving actually saves energy; I've always assume that having once converted electricity to motion, it's far more efficient to just coast when you take your foot off the pedal than to convert it back to electricity. If I'm trying to drive my EV efficiently, I put it in D mode (behaves like a regular auto transmission, more or less, but regen on braking) and do my best to stay at the speed limit on uphill or level ground, coasting up a bit above the limit on downhills, and letting myself coast in to a red light instead of keeping my foot on the pedal until I'm close & then braking.
Coasting isn't braking. If you want to coast just don't completely release the accelerator pedal, only up until the point where you're no longer accelerating or braking.
You don't need a dead zone. Just modulate the pedal to whatever level of acceleration you want. The car will either regen a little, use a little power or use next to no power if you're at the perfect inclination.
Energy from going downhill (assuming it's steep enough to overcome drag and rolling resistance) can go into either of two places: increased speed or charging your battery. The only difference compared to an ICE is that you only get the first option when going downhill (or wasting it into heat via the brakes).
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?
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.
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.
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.
I'll say this as someone who's been driving for over 20 years, probably about 250,000 miles, and has owned an EV for just over 3 years...
Maintaining a constant speed on a flat highway isn't hard, but doing it on terrain that goes up and down a lot is much harder in an EV. Maybe it's because every car I've driven before was a manual, but I got really in tune with judging my speed based on my car's engine sound. The visual change going from 60 mph to 70 mph because you started going downhill is not nearly as obvious as the change in engine note as the RPMs rise.
Going through the hills on I-5 near the Oregon/California border, cruise control is an absolute MUST in an EV.
Coasting can be more efficient. For instance, on the hyundai ioniq 5/6 1 pedal is typically the most efficient mode for around town driving, though a skilled driver may be able to beat it on one of the lower regenerative modes but it its a good deal of cognitive load for marginal benefit. You can also enter into a "auto regenerative mode" when using adaptive cruise control on the highway this mode will mix in coasting and has the highest efficiency.
True hypermilers are crazy, IMO. But most drivers can certainly learn from them.
When I drive an ICE, I drive like I don't have a brake pedal because it's an evil device that converts cash into heat and brake dust. The light ahead turned red? Take the foot off the gas. No sense maintaining speed if I'm just going to stop. Driving through a large dip? Let the car speed up as you go down so you'll give yourself momentum to climb out.
It blows my mind when I see someone driving up hill, notice they're going too fast, and they hit the brakes rather than just let gravity do the job.
My previous car was a Subaru BRZ, stickered at 24 mpg city, 30 mpg highway. I averaged 33 mpg. I didn't even drive slow. I just made sure that speed was never wasted unnecessarily.
Yes this is also Porsche's position,[0] which I believe is actually superior to the Tesla way. Of course the best option would be to let the driver choose between modes.
Letting off the pedal gives an easy way to explicitly command "torque sleep"[1] on the motor, which saves even more energy.
I wonder if its more due to the fact if you're used to one pedal driving you're never touching the brake and thus practically never engaging the friction brakes.
My wife uses traditional driving in my EV, I use single pedal. While she's pretty good at keeping it in the regen-only braking zone, pressing just slightly too hard will end up having some percentage go to friction brakes. I just never touch the brake pedal, so I never engage the friction brakes.
This ought to be solvable by adding some haptic/force feedback through brake pedal? For instance have a distinct click at some point in the pressure curve that means "at max regen braking" and if you keep pushing there's a bit of resistance and then another slight click that means you're engaging the friction brakes? Placed close together in the pressure curve, but still distinct enough to get consistent results?
You can have coasting and regen braking with traditional two pedal driving. With Toyota's hybrids, for example, using the brake pedal engages regen and only engages the brake once you need more braking force than the regen can provide.
Converting kinetic energy back into something you can use later to accelerate is less efficient than dissipating it as heat you can never recover? I don't follow your math.
I’m not even sure what I meant. More sleep needed.
Edit: While coasting might be more efficient than braking, regen braking is probably more
efficient than using brakes. (Which might explain the overall efficiency improvement when using one-pedal driving even if we assume coasting is more efficient than braking)
Depends on the car, mine (Polestar 2) uses regen braking regardless of whether one-pedal driving is selected. The consensus seems to be that coasting is slightly more efficient but barely enough to make a difference.
I've always felt that brake lights should be somehow encoded with the actual rate of deceleration not just the binary on/off of the brake application. It would make it much easier to gauge from a long distance how urgently people ahead of you are braking.
They are, at least on my car and many other here in Europe. Brake past a certain threshold of deceleration, and the brakes lights flash rapidly, indicating to motorists behind that rapid deceleration is occurring. I’m not sure what the threshold is.
In my experience the threshold is high enough that it only helps you distinguish between "incredibly sudden but non-emergency stop" and "full-on emergency stop"
What kind of vehicles do you see this on? I have only rarely seen this, perhaps because it's not common in the US, or perhaps because emergency braking isn't all that common. But if there's going to be a different kind of light behavior, I'd think they'd want to have it triggered commonly enough that people would know what it means. Otherwise they might be confused the first time they encounter it.
Automotive engineer here. What the article and many posts here miss: one pedal driving is just another user interface mode to capture the driver’s intent. The system itself always recuperates energy instead of braking, if possible. If no intent to decelerate is given, sailing is more energy efficient than recuperating.
It sure beats three pedals though right? If you wanted to completely optimize you would introduce some kind of regen break pedal which allows you to stop using regen only and then switch to your backup break pedal when you have too short a stopping distance. Ux is pretty bad I imagine.
Some EVs use paddles behind the steering wheel to control recuperation. You can switch between several levels or use max regen while you hold one of the paddles. It gives a lot of control without touching the brake pedal.
I wouldn't want that kind of interface. I'd worry about it retraining my mind to think "Braking = pulling this paddle", and then one day I'll need to make an emergency stop, and I'll pull the paddle instead of hitting the foot brake and ram into whatever I wanted to avoid because the regen braking was insufficient.
I suppose the system could be designed to detect a user suddenly putting a death grip on the paddle brake and apply the foot brake automatically.
Brake lights are not only about showing deceleration, but also intention.
If I tap the brake and it doesn't really change my speed, it still signals to those behind that I was (for whatever reason) think about slowing down, which is useful information.
So I think brake lights should come on when deceleration is greater than a certain value, OR when the brake pedal is pushed.
I think it's interesting but I've also never had to brake quickly with it and I worry my brain would fail to jump back to the brake. I suspect it'll end up being more dangerous in the long run unless cars auto brake better.
Been using it for about 3 years. Your brain honestly figures it out pretty quickly. One pedal ramps the longer your foot isn’t on the pedal like a slow roll so you always instinctively think to hit the brake pedal if you need to stop with any urgency.
It depends on the car I believe. My Mach E doesn't brake as hard as Teslas that I've driven and honestly I'm braking too late more often than I do with normal 2 pedal driving. Mentally it just adds a split second of hesitation because I can't judge as precisely how quickly my car will come to a full stop. The Teslas that I've driven are nice because they brake much harder, which I personally like.
At least in my car, it's not a problem. You can use one-pedal driving most of the time but the regenerative brakes aren't nearly as strong as the mechanical brakes so the mechanical brakes are still used. If for example you're coming up on traffic lights and they turn yellow, you won't be able to stop quickly enough with the regenerative brakes but you will with the mechanical brakes. Through little things like this you quickly build muscle memory for the mechanical brakes.
I've been doing it for a number of years, and haven't found that to be a problem. My brain doesn't consider one-pedal driving as equivalent with a hard stop, it's more about modulating my speed with high precision. If something jumps in front of me that necessitates emergency braking, I use the brake pedal like I always have.
As a Tesla driver, I’m used to one pedal driving now, but I don’t love it.
The thing I do most when driving is maintain the same speed, and doing that with one pedal driving is a little hard on my leg, since you have to keep the pedal at just the right angle. I’d prefer a “sailing” mode where one pedal accelerates, the other decelerates, and if you do neither then it just maintains your velocity.
The Tesla already disconnects the pedal inputs from what’s happening since I have the setting turned on for it to maintain one-pedal deceleration when regen is low, by adding in brake. I’d like to continue heading in the drive by wire direction.
Cruise control? If I'm keeping the same speed for more than like 5ish minutes I usually just turn on cruise control. So many cars have adaptive cruise control, and it often works in traffic pretty well. Many cars even handle stop and go in adaptive cruise as well. Both of my cars even let you set it digitally from the steering wheel, so I can accurately change my speed without touching any pedals at all.
When I first got it, one-pedal driving wasn't implemented yet. Regen had a "low" and "high", and at first, I used "low", but found myself still using the foot brake to decelerate from high speeds. I change it to "high" after only a week or two, and it became exceptionally rare for me to use the foot brake.
It doesn't feel sluggish at all. You just have to get used to maintaining constant throttle input unless you want to stop. It's a bit of a retraining, but I learned it quickly.
Maybe it's because my previous cars were both manual transmissions which will always apply engine braking, especially in lower gears, so I was used to merely reducing throttle instead of completely removing it when I wanted to slow down a bit.
I use High + Hold and I don't think it makes the car feel sluggish at all. It just takes a little bit of mental training to get used to not completely releasing the throttle until you're under 10 mph unless you really want max regen braking, which for comfort reasons, is rare.
To me, what makes a car feel sluggish is...well...being sluggish and having no power. Since I have the Model 3 Performance, that's not a problem at all. :-D
I've been driving a Chevrolet Bolt EUV since mine was delivered in April, 2023. For the first six weeks, I avoided One-Pedal Driving since I thought it might impair me driving a regular car.
I switched to using OPD and I can't imagine going back. When I was younger, I drove only manual transmission cars and liked the feeling of being integrated with the car that shifting gears gave me. In the US, that's left hand on the wheel, right hand on the gear knob, left foot on the clutch, and right foot on the gas or brake.
At the time, I believed that only people using a manual were "drivers", everybody else was a "steerer". OPD only uses one foot and one or two hands on the wheel but for me, the feeling is somewhat similar to the manual as the car reacts quickly to my right foot.
I use adaptive cruise control a lot, even on city streets. My ICE cars would not let me set cruise control below 25MPH but the Bolt lets me set it at anything I want. That (presumably) gets me around the issue of not being able to coast - on cruise control, the car will coast when it wants, accelerates when it wants, use re-gen when it wants.
As a die-hard manual enthusiast, it’s hard to love one-pedal driving.
With a manual, I can accelerate, maintain my speed, coast in neutral, brake, use my transmission to slow down, or modulate low speeds with the clutch partially engaged.
I find it to be the opposite. Re-gen braking is very close to engine braking in a manual transmission car (before the modern "rev hang" tuning to prevent people from stalling) - I love it.
I still drive a manual transmission car, but don't mind the one-pedal if I were to switch to an EV.
I drove a six speed manual for 16 years and loved it, and almost always used engine braking. The regenerative braking the electric I drive now feels very similar, with maybe two exceptions.
Where my manual would stall, my electric comes to a gentle stop.
You also don't get the same sort of "neutral" feeling. You can get close, but it's not like shifting to neutral and taking both feet off the pedals and coasting. You have to simulate it with your foot and pedal position. It becomes second nature, but it is a difference.
Aside from that, it's the same to me. My right foot can still come all the way off the pedal and apply more braking, just like it would if I were engine braking and needed more. I feel fully in control.
Ha, that's weird, I'm the opposite. I love manual transmissions, and anticipate that I'll always have a manual sports car in my life. But I also love one-pedal EVs. Such precise control, which is part of what I like about the manual. It's slushbox automatics I have no real love for.
It's definitely not the same as driving a manual, but adjusting the regen level in my car sort of feels like shifting. e.g. "shift" into full regen to stop, shift into no regen to coast when I see brake lights but they're still a mile ahead.
I did a bmw performance driving event in the i4 m50 and 330 hybrid on a closed autocross course, as a manual enthusiast it's the closest to driving my 6 speed.
What was the impetus for manufacturers to design it this way I wonder? It seems to me like you could easily implement regenerative braking in the same way by having the brake pedal respond to light pressure with regenerative braking, and firm pressure with brake pads. Then you don't lose the ability to coast, nobody has to learn anything new, and you don't have to transition from pedal to pedal if you need to surpass the capability of the regenerative brake.
Was there an engineering challenge? A safety concern? Do they think that using a single pedal has enough innate advantage that it overcomes the disadvantage of having to be learned? And if so, what's the innate advantage?
> It seems to me like you could easily implement regenerative braking in the same way by having the brake pedal respond to light pressure with regenerative braking, and firm pressure with brake pads.
It already works exactly like this. It's called "blended braking".
One pedal driving is a different feature. It's intended to get even more regen, by encouraging more gradual deceleration. If your habit is to already avoid hard braking, then it doesn't really increase efficiency because you'll get the same benefit from the brake pedal.
> using a single pedal has enough innate advantage that it overcomes the disadvantage of having to be learned?
For me, the learning period would be best measured in minutes. It feels extremely natural. When I bought my Bolt I turned on One-pedal mode and I haven't turned it off a single time.
Today's cars have loads of technological regressions -- touchscreen head units, expensive proprietary headlights, removal of 3.5mm audio input, telemetry -- but one-pedal driving is very clearly a progression as far as I'm concerned.
Every car with OPD I've been in also had an option for a more typical "coasting" style, where you need to use the brakes. I've been driving cars extensively for 22 years, and picked up one pedal driving during the test drive of my EV. 4 years later with 95% of my miles done using OPD, the urge to smash the brakes is still there if I need to stop quickly. Having said that, I have no idea how new drivers who spend 100% of their time on OPD will handle actually-using-the-brake situations.
Give me an idea of how often you'd hit the brake pedal while trying to use one pedal. A few times an hour? Week? I feel like if it's a regular enough thing the natural impulse would be there for new drivers too, but if it's something you're doing every couple months, probably not.
> And they have lots of unexpected behavior and non-linear brake feel.
Upthread there are several examples of brake lights not going on when people expect, or the regen braking being hard to get to feel right. All new systems are going to be buggy or whatever for a while, varying from model to model. I just haven't heard why putting regen on the brake pedal is uniquely difficult.
> and it is easier to adapt to this on the accelerator pedal....Blending between regeneration and brakes is just about impossible to get right - it will be non-linear and make you worse at braking.
I learned to drive mechanical transmissions, and in fact my pickup truck is the first vehicle I've ever owned with an automatic transmission. I also ride motorcycles. "One pedal" or "compression" braking is a given; the control you have over how strong it is is the gear you're in, which also sets available torque for acceleration (and inversely impacts efficiency, because an ICE is a big air pump).
I routinely downshift the automatic transmission going downhill on twisty roads or in parking lots, and it definitely provides compression braking when your foot comes off of the accelerator, without touching the brake. I taught my adult spouse to drive and one of the ways I tempered hesitancy was to have her shift the automatic transmission to a lower gear (but not so low she'd over rev the engine driving the speed limit). I was less concerned with fuel efficiency or whether she sounded like a hot rodder than I was with providing her positive control over speed. I'd say it worked. Mostly now she only downshifts going down hill or in parking lots.
I use my brakes sparingly myself. I think many forget there is something between pushing the gas and hitting the brake, and that is foot off both, especially on highways you can really control your speed with wind resistance. I also like to downshift on steep grades when going downhill, and I downshift when traffic gets backed up common on NYC highways.
The concept of one pedal driving should be entirely divorced from the concept of regen. It’s purely a UI choice.
One could just as easily (ok it’d be slightly harder) design a system that behaves just like a traditional ICE vehicle while still regenerating the exact same amount of energy.
Any argument for one pedal driving should be centered solely in the UI benefits (less foot movement, etc.) rather than even mentioning regen.
I used one-switch-driving most of the time in my non-electric BMW 5. The cruise control up-down switch (+/-10km clicks, +/=1km nudges) on the steering wheel was very convenient to operate. The acceleration very smooth, as was
the regenetative braking deceleration. I consistently had better fuel economy that way than other drivers with the same model.
Everything has to allign though for this to feel great. I have tried it with other cars, and it never felt as good.
> How did you have regenerative braking on a non-electric BMW 5?
Just because the EV-brigade gave it a fancy name doesn't mean they invented it. ;-)
The non-electric synonym to regenerative braking is the combined effects of engine braking and/or tyre friction.
I frequently use it myself, for example when I'm approaching a known reduction in speed limit and its safe to do so (in the context of traffic distance behind me) I will disable the cruise control and let the car slow itself down in a relatively short distance.
After a short while you can do that sufficiently accurately so you reach the exact speed limit by the time you reach the sign post.
EV's basically do the same thing. The "regenerative" part is a bit overhyped IMHO it won't magically recharge your battery, maybe add 5–10% over the course of hours if you're lucky with the electron gods. The laws of physics still apply in an EV, unfortunatley.
Yes you might try to argue that EV regenerative braking slows you down faster. But the more aggressive nature is a double-edged sword ... aggressive slowing down with close following traffic, for example, is a recipe for easily avoidable disaster.
Just because the EV-brigade gave it a fancy name doesn't mean they invented it.
What you describe isn't regenerative braking by any stretch of the definition. Just because one considers "regenerative" to by hype doesn't mean one gets to use the word incorrectly. I guess the flip side of "pedantic" is using a word incorrectly even when one knows it's being used incorrectly.
Interesting; I thought the term referred to the fact that electricity is being generated in the process. This appears to be the DOE's definition also. [1] I'd be curious to see how it was used before this, like you say!
> I thought the term referred to the fact that electricity is being generated in the process.
If we are being pedantic about it, yes, you are right in your thoughts and certainly that is what the EV manufacturers want you to think via their marketing.
But the reality is I guess you could say 95% of the "benefit" of regenerative braking is the braking side of things (and so therefore similar to the non-EV equivalent).
There is, without argument, the remaining 5% "benefit" of the generation of electricity. But certainly in my own experience of driving EVs for both long road-trips and short journeys is that the electricity generation is largely manufacturer hype. Why ? Because basic physics dictates that you're playing a net-net zero-sum game ... i.e. what you "generate" you then loose when you next stop at the lights and accelerate again, or when you next overtake a car on the highway or, or, or .... so in the end you might end up with perhaps a 5–10% net gain if you're lucky which isn't really all that much to sing and dance about.
Can you explain what the word "regenerative" means in the context of an ICE vehicle decelerating? Your description above doesn't indicate that anything is being generated.
You indicate that the generative impact seems trivial, but this is not the case for me. In my PHEV, I get an additional mile of range when I brake regeneratively getting off the freeway. This is non-trivial in a vehicle that only offers about 12 miles of EV range. It's one of the reasons that my average MPG hovers between 90 and 100.
It's not pedantry; you're just taking two roughly analogous things and acting like they have no differences. It IS relevant that EVs call it "regenerative braking" because it does "magically recharge the battery".
> that is what the EV manufacturers want you to think via their marketing.
And yet we're in a thread for an article from the U.S. Department of Energy, not a car manufacturer.
> Because basic physics dictates that you're playing a net-net zero-sum game ... i.e. what you "generate" you then loose when you next stop at the lights and accelerate again
You're missing the point entirely. The point of regenerative braking isn't that it's more efficient than maintaining a constant speed the whole time. It's that it reclaims energy when you would have to stop anyway, traditionally with the brake. i.e. city-driving when you hit stop lights.
A 5-10% net gain is an incredible benefit; I don't know why you're downplaying it. If I could make a 10% improvement to my fuel economy solely by coming to a gentle stop (which I already do anyway) it would be amazing.
No I'm not. I retain my argument that it is a zero-sum game.
The manufacturers would have you believe it's a one-way gain and you can magically recharge to 80% again through regenerative braking, but in the end it almost entirely nets out. So a lot of it is marketing fluff.
That's the point.
> If I could make a 10% improvement to my fuel economy solely by coming to a gentle stop (which I already do anyway) it would be amazing.
For all you know, you probably do.
Its just that your ICE doesn't have some fancy display pumping out the numbers to make you feel all cozy about it.
Why do you think haulage companies spend an inordinate amount of time and money on driver training beyond the obvious parts of the training ? Because driving style can affect fuel economy, sometimes substantially.
Opening my thesaurus: what do you regain/recoup when you use regenerative braking on an internal combustion vehicle? If the answer is "nothing," that's just decelerating or "engine braking" in my opinion.
Some BMW 5s can do regenerative braking and use it to charge the "normal" (well it's a big stop-start one these days I would think) battery instead of having the alternator load the engine. So the electrical systems can be running on regenerated power.
My EV has a “paddle” on the steering column that you can pull towards you to engage regenerative braking. I use the actual brake pedal maybe 20% of the time or if I need to do a quick stop to avoid hitting someone in front of me. I did like this sentence in the article: “Before stopping, take your foot off the gas and allow the vehicle to slow down naturally to a complete stop.” Off the gas?!
That's an interesting thing. I wonder if 30 years from now, cars will all be electric but the pedal will still be called the "gas" pedal. It will be one of those words that kids don't understand where it came from, like "dialing" a phone or the file save icon.
> However, there are three conditions where it’s not safe to operate the one-pedal driving mode:
When driving on slippery roads, such as ice, slush, or snow.
During a downhill drive.
If you fill your car with heavy baggage or cargo.
I use one-pedal driving downhill all the time. I typically take my foot off the accelerator and hover it more over the brake pedal. Is there a reason this would be unsafe?
The regenerative braking in the latter two cases may not be strong enough to stop the car. If you hit the brake pedals it engages the old-fashioned brake calipers and stops the car like it's 1935.
How would this be worse? You can press a single pedal instead of switching between 2 pedals. Cruise control is still available in one pedal mode if you want to give your "gas foot" a... break.
I mean GP specifically mentioned "no cruise" and while I doubt that's common in EVs, to their point in an ICE you can take your foot off of the gas, do some stretches, give it a quick rest, and put it back on the pedal all before you would noticeably change speeds. In an EV with regenerative braking you'd be noticeably decelerating if you did the same. I think that's what they were reacting to; the idea of not being able to give your foot a rest. But again...your EV is probably going to have cruise.
Cruise fails when there is any sort of traffic. You can never match the flow right.
Now with autopilot on newer cars as I understand it this is less of an issue but anything with standard cruise control is only gonna work on the interstate most of the time and often not well then.
Loads of cars, especially EVs in particular because they're normally based on higher trim levels, have adaptive cruise control as at least an option with many cars having it standard. Every Honda has adaptive cruise control standard, for example.
I tried one-pedal in my EV6 for a few months, but found it fairly tedious with the aggressive braking. The EV6 does give you four levels of sensitivity if you want less than one-pedal, but I ended up switching to auto mode, where it dynamically adjusts the braking level and regen based on vehicles ahead of you.
Why not use it when driving downhill (as the OP says)? It seems like you'd gain more regenerative braking energy. Does the energy exceed the battery capacity? Is it hard to choose the right amount of pedal pressure to maintain appropriate speed?
I don't know why someone would recommend not using regen braking going downhill. That's the absolute BEST time to use it! It's literally free energy!
There's a hill I drive down any time I go downtown. I'll gain 1-2% of my battery back every time I go down it.
> Does the energy exceed the battery capacity?
When that happens, you just don't get any braking and you have to use the foot brake.
> Is it hard to choose the right amount of pedal pressure to maintain appropriate speed?
Can be. The accelerator can be pretty sensitive while going downhill. Just use cruise control, as it'll modulate the regen braking as necessary to maintain a constant speed while going downhill.
Much like you don't always press the brake pedal all the way down when you want to slow down, don't release the accelerator pedal completely, only the necessary amount. You're 100% in control of how hard OPD braking is.
If 0% throttle is maximum regen braking, and 20% throttle actually keeps you coasting, then...just try using 5-10% throttle. Your throttle is not a binary switch. Handle it with more finesse.
> In most EVs you can control the intensity of one-pedal breaking.
In all EVs you can control the intensity real time with your foot. I concede, though, that I have friends whose driving style is best described as "binary" and I imagine they wouldn't be big fans of one-pedal mode.
Yes, your foot is the ultimate the control. However, there are settings for the steepness of the maximum deceleration for the scenario where the foot is completely lifted.
None of the benefits listed apply to the Chevy Bolt, as it uses regen up to 55kW when using the brake pedal. I would assume most modern EVs are the same.
One pedal driving allows us fine motor control without a drastic switch. The regenerative braking also encourages us to not over-brake (you grow to love the idea that you are recapturing energy and avoiding wear on the pads).