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The NTSB considers the low gear regeneration braking (sans paddles) with no active brake light to be no different than braking using down shift in a car with a manual transmission.
Not really. Manual transmissions have an exemption to the braking rate requirements for lighting the brake lights. All other vehicles must light them up whenever slowing faster than a certain rate. There's also a deceleration range where they're optional.
 

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One thing that I did find out that's pretty cool with a gen 1 volt that has forwarded collusion alert. If you have it in L with cruise on if you get close enough to turn on a warning it will automatically kick it to high regen just like automatic braking.
 

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That's odd, because if I'm in L and I completely lift the "Torque Request Pedal" HAHA, my brake lights illuminate. 2016 Gen2.
I have a GEN two 2019, as I always have my bike rack on my car I can easily see when it gets a little darker how it operates and yes, if you take your foot off the gas, the brake light will illuminate, as well as with the paddle
 

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Hello, all, new Volt owner here. (Edit to mention it's a 2011)

When driving in L, and letting off the acceleration to slow the car down- do the brake lights activate?
Having been rear ended in a bad accident in the past, I'm a bit more hypersensitive to the possibility.
Slowing down as much as the Volt can without using the brake pedal has me worried about catching other drivers off guard if there's no indication.
I too use L exclusively. In light traffic, with plenty of notification prior to an impending stop, no brake pedal is required until the stop. In denser traffic some brake pedal may be required to increase the regenerative braking thereby illuminating the brake lights. Even with partial brake pedal, regenerative braking releases at 5 mph. The release can be felt and additional pressure is required to apply the friction brakes.
 

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Regen doesn't 'release', it is simply that the motor/generator is spinning too slowly to produce the electric current at a rate necessary to continue deceleration at the driver's desired vehicle slowdown rate. Unlike friction brakes, the slowing force of regeneration diminishes as the vehicle slows.
There's also the onset of "idle creep" that GM uses to mimic an ICE with automatic transmission. At that speed threshold the motor/generator transitions from a regenerating deceleration device to a motor.
If the driver wishes to slow to below this 'idle speed', the brake pedal has to be pushed into the hydraulic friction brake actuation range.

Gen1 do not activate the brake lights regardless of regeneration created deceleration rate. Gen2 apparently do, and I wouldn't be at all surprised to learn there's a brake light switch built into the paddle operated regen on those. Could someone with paddle regen in their Gen2 check if the brake lights come on by simply pulling the paddle when stopped, in D, and foot off the brake pedal (like pulled up to a wheel chock, diagonal parked at a curb, parking lot curbing)? That would demonstrate that it is not deceleration rate that activates the Gen2 brake lamps in regen, but that there is a means, one not related to deceleration rate, that activates them.

Me? "L" mode has no purpose for existence and is a useless wasting of internet bandwidth.
The foot brake has a 'nearly' infinite range of regeneration capacity, "L" has a single range. If the driver wants more or less deceleration than the mandated "L" level he/she uses the pedals to vary that amount: Accelerator to reduce the amount, brake pedal for more. Just like "D"
L does not increase range. The power consumption of motor operation is exactly the same when accelerating or driving at constant load. L does not increase regeneration electric power recovery any more than applying the foot brake to the same level. Driving down a hill at some speed in L recovers no more power than driving down that same hill using the brake pedal to hold that same speed. Decelerating at the L defined rate recovers exactly the power recovered in D and using the foot brake to decelerate at that same rate.

L does not increase torque/pulling power. There is no "low" gear ratio that trades away mph to gain ft*lb.

L, in the Volt, is bordering on Chindogu. The issue preventing it from meeting the requirement of true Chingodu is that its uselessness is not recognized universally. I'm working on that....
 

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L has a FANTASTIC place in my world: combined with cruise control, it makes for a rock-solid speed control in varied terrain and no worrying about radar guns in bushes at the bottom of hills. I don't use it to stop or slow the car, and if I'm NOT using cruise control, I'm probably in D because the long roll is fine then, and constantly carefully feathering the accelerator to manage speed makes my shin hurt.
 

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"L" may be beyond useless... I would contend that it actually reduces your range/efficiency since it is needlessly regenerates on slight downhills i.e. your car starts picking up speed on a slight downhill, so you lift off the accelerator. The car will regen in L wasting your momentum. In D, the would regen far less and maybe allow your speed to increase slightly, but it would maintain most of the potential energy without needlessly (and wastefully) converting it to electrical energy to be stored in the battery only to be transformed once again when the road inevitably flattens out or starts up the next hill...
 

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I switch between D and L. L produces a noticeable "drag" feeling whereas D feels more frictionless. I use L to feather my stopping distance but otherwise use D.
 

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Good post that points to more details.
See regs and how the Volt compares here: Brake Light Actuation also compares amount of Volt L deceleration to that of manual downshifting in other cars.

Summary: The Volt's L deceleration is below the limit (JUST below) requiring the brake lights to come on, while a Mustang 3-2 downshifting is 2X greater than the Volts, Accelerating a Mustang in 2nd and then taking your foot off the pedal (no downshifting) also decelerates faster of the Volt in L. All this is to say, the Volt in L meets the existing safety regulations for brake lights and is certainly less of a hazard than at least some cars with a manual transmission that are downshifting or simply not accelerating.

The "I Feel" comment almost always comes up when the poster desires the brake lights to come on while in L, regardless of the law or facts. But it's a feeling rather than a fact. and there is a simple solution, don't use L or tap your brake pedal if you "feel" unsafe.

Keep in mind it is a fact that brake lights do not prevent being rear-ended. An inattentive driver will rear-end a parked car, a car with brake lights on, a police car stopped with all it's lights going. Happens all the time. But if it makes you "feel" safer to have brake lights on, then tap your brakes or drive in D.
 

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Funny how a “quick question” ends up becoming a major discussion!
 

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Discussion Starter · #33 ·
Tapping brakes in L means hitting the full decel speed as you fully take your foot off the go pedal. I'm not about to bring the left foot into the equation lol.
Must've been a big enough issue to have introduced the paddle in later years.
 

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Tapping brakes in L means hitting the full decel speed as you fully take your foot off the go pedal. I'm not about to bring the left foot into the equation lol.
Must've been a big enough issue to have introduced the paddle in later years.
I suspect it was a not-expensive part to throw in for a little fun, and in the same vein as "Sport" mode. And also similarly, neither has an particular impact on the performance of the car overall. You're never going to see huge changes to how the car behaves. Sport Mode won't make your car zippier than stomping on the long pedal all the way already would, and the regen paddle won't stop the car any faster or more efficiently than the wide pedal can.
 

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"L" may be beyond useless... I would contend that it actually reduces your range/efficiency since it is needlessly regenerates on slight downhills i.e. your car starts picking up speed on a slight downhill, so you lift off the accelerator. The car will regen in L wasting your momentum. In D, the would regen far less and maybe allow your speed to increase slightly, but it would maintain most of the potential energy without needlessly (and wastefully) converting it to electrical energy to be stored in the battery only to be transformed once again when the road inevitably flattens out or starts up the next hill...
And that's the sole set of conditions that the regen actually DOES work to increase range. Whether brake pedal, or paddle, or L, with or without "paeddle", the lowering of road speed also reduces air drag. You can continue to 'coast' at an increasing speed and let the kinetic energy be squandered to create a bigger breeze, or you can slow down, have an easier time pushing air aside and 'bank' that air drag reduction as more regenerated electrons.
The gain in energy collected by going slower down the hill (more electric potential and less kinetic momentum energy gain, AND less loss to air drag) will get further up the next climb than will a faster down hill drive (less potential recovery, more kinetic momentum, and much greater air drag loss).
 

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I've confirmed my 2017 Volt lights the brake lights in L. Confirmation done at night and watching the reflection off signs behind me when I let off the throttle. It also triggers the brake lights when using the regen paddle. Same confirmation method.
I agree. I verified using the same method on my 2017.
I have also had the occasion to follow a Volt which I decided was driving in "L". His break lights were coming on and off randomly. It was kind of unnerving. It does make followers back off a bit
I also found out that if you drive with "L" and cruse control, the car will maintain speed even downhill. In "D" with cruse, the car will speed up going downhill like other cars.
 

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Discussion Starter · #37 ·
Either I ran out of nerve or the car didn't do what another poster had claimed, saying the volt will automatically apply braking when on cruise and approaching a car in front using proximity sensor info.
I got uncomfortably close to the car ahead on cruise/L before I manually eased off, I'd say 10 feet at 65mph (less than a car length). 🤷‍♂️
 

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Either I ran out of nerve or the car didn't do what another poster had claimed, saying the volt will automatically apply braking when on cruise and approaching a car in front using proximity sensor info.
I got uncomfortably close to the car ahead on cruise/L before I manually eased off, I'd say 10 feet at 65mph (less than a car length). 🤷‍♂️
Note that post #23 was speaking about the Forward Collision Alert (FCA) system, not to be confused with the Ultrasonic Front and Rear Parking Assist (UFRPA) or the Ultrasonic Rear Parking Assist (URPA) systems, all of which are "if equipped" features (i.e., extra cost, not all cars are so equipped). Information on the FCA was first included in the 2013 owner manual, so it’s doubtful your 2011 Volt is so equipped.

The FCA system will flash the icon on the display and sound several beeps when triggered. From the 2019 Volt owner manual: "When your vehicle approaches another detected vehicle too rapidly, the red FCA display will flash on the windshield. Also, eight rapid high-pitched beeps will sound from the front... Cruise control may be disengaged when the Collision Alert occurs."
 
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