By Phil Royle – Feb. 1, 2022

I find one-pedal driving in EVs has its benefits in certain situations, although I must admit that I prefer manipulating the brake pedal myself. Is that so wrong? Regardless of my personal preference, however, I wanted to know whether one method was legitimately and definitively more efficient. But while I seem to have found the answer, it’s not as overwhelming as one might hope.

Seemingly every “true” EV enthusiast touts the benefits of one-pedal driving, where easing off the gas pedal slows the vehicle – often to a complete stop – through the use of resistive magnetic forces in the EV’s motor(s), thus generating power to replenish the car’s battery pack.

In my use of one-pedal driving, I can cruise for days without touching the brake pedal, which means those trips are guaranteed to never engage the friction brakes and should, in theory, provide some of the highest levels of deaccelerating efficiency the EV can provide.

In many ways, the Nissan Leaf brought one-pedal driving to the masses. But can an EV be just as efficient with the driver using the brake pedal instead? Well, it depends. (Image courtesy Nissan)

That said, I prefer to use the brake pedal. I feel more in control when I decide when, and how much, to apply the brakes. And, if you must know, I also like to stretch my right foot while coasting down hills. And it’s not like all EVs just freewheel with zero regen when one-pedal driving is deactivated or reduced – it seems many EVs regen a little in order to mimic the engine-compression braking ICE vehicles have.

However, while I prefer to brake via the left pedal, I do believe there is a side effect: One-pedal driving will make more people safer drivers, as they will not wait until the last moment to hit the brakes – they know the car’s regen isn’t going to rapidly deaccelerate, so they’re more likely to look, and thus plan, ahead. Ultimately, this leads to more time reducing speed, which means the driver is not on the power as long (which is more efficient), and it should reduce rear-end collisions (which is, obviously, safer for everyone).

But using the brake pedal doesn’t mean you’re using friction brakes. Seemingly with one (very notable) exception, EVs use blended braking, where the brake pedal initially utilizes regen to slow the vehicle, engaging the friction brakes only when necessary.

The Ford Mustang Mach-E, for example, activates regen when the brake pedal is pressed and then blends in the friction brakes if needed. This appears to also be true with the Rivian R1T, Porsche Taycan, Polestar 2, Chevy Bolt, plus Hyundai’s Ioniq Electric and Hybrid, to name a few. Heck, even the Prius uses blended braking.

For those vehicles, if you can mimic one-pedal driving’s deacceleration rate, there should, in theory, be little difference in efficiency between one-pedal driving and utilizing the brake pedal.

This, though, is in theory. I wanted an answer.

(An aside before getting to the answer: The very notable EV exception to blended brakes is Tesla. Tesla opts not to utilize regen with brake pedal application; instead, Tesla solely relies on one-pedal driving for regen, and the brake pedal for friction brakes. Knowing this, there is likely no way to make a Tesla as efficient with low regen settings. If you want to drive efficiently in a Tesla, then crank up the one-pedal regen. For those not driving a Tesla EV, read on…)

A few studies and simulations have tackled this very topic, trying to discover the most efficient method of driving EVs that feature blended brakes. According to one study that used simulations in addition to a custom-built EV, the TU/e Lupo EL BEV built by the Eindhoven University of Technology (it’s a converted VW Lupo), energy efficiency increases by 2-9% with one-pedal driving engaged, with another study putting that number at 5% through its research with a Chevy Bolt.

In tests and simulations, Eindhoven University of Technology found their converted VW Lupo BEV was 2-9% more efficient utilizing one-pedal driving compared to blended braking. (Image courtesy Eindhovel University of Technology)

To put that into perspective, on a 250-mile range EV, that translates to somewhere between 5 and 23 miles over the course of the entire battery range. If you only drive 60 miles per day, you’re talking about a potential 1.2- to 5.4-mile advantage utilizing one-pedal driving instead of applying the brake pedal manually for EVs featuring blended brakes (ie: nearly every EV except Teslas).

Read as I might, though, it seems the first study’s simulations didn’t work into the equation the tiny bit of regen some EVs offer even with one-pedal driving turned off. So, that 2-9% increase in efficiency for one-pedal driving might be a tad high in cetain applications – not much, but a little.

That said, I did enjoy seeing the second study mention that I’m not alone in foot fatigue:

The driver can choose from a selection of driving modes according to the current traffic condition. For example, the traditional driving mode should be selected during high-speed, long-distance drive to help avoid foot fatigue caused by long-term deep pedaling on the accelerator pedal.

Less scientific real-world tests also exist, although they introduce more variables and should be considered anecdotal. This test performed in a Polestar 2, for instance, concluded that there is no measurable, real-world difference between one-pedal driving compared to using the brake pedal, undoubtedly thanks to blended brakes.

The efficiency level also likely varies depending on whether you’re driving around town or on a flowing freeway, as that 5% efficiency bump in the Chevy Bolt came under busy road conditions.

To my chagrin, it appears that one-pedal driving is either just as efficient or more efficient than manually applying the brake pedal in blended-brake EV applications. That said, the efficiency difference is so little that it probably shouldn’t make a difference which you choose.

So, I say pick the method you prefer and go for it – that’s what I’m going to do.

(Main image courtesy BMW)

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