No brake lights in D- or D-Auto

I don't get it: why don't the brake lights come on when the car is at maximum regen? This is the case with the Tesla and eGolf, and should be standard. Today alone I got three people gesturing at me during my commute home, and people always run up really close not clearly seeing that I'm slowing down at a pretty good clip. I know, I could step on the brake, but that undermines the whole D- and D-Auto idea. This is something that could be easily addressed in firmware.

phototrek said:

I don't get it: why don't the brake lights come on when the car is at maximum regen? This is the case with the Tesla and eGolf, and should be standard. Today alone I got three people gesturing at me during my commute home, and people always run up really close not clearly seeing that I'm slowing down at a pretty good clip. I know, I could step on the brake, but that undermines the whole D- and D-Auto idea. This is something that could be easily addressed in firmware.

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Maybe write a letter to Mercedes, tell them this is a pretty serious safety issue, maybe then they will update via firmware. This is a compliant car (probably for only three years), they are not motivated to do anything extra.

tom said:

phototrek said:

I don't get it: why don't the brake lights come on when the car is at maximum regen? This is the case with the Tesla and eGolf, and should be standard. Today alone I got three people gesturing at me during my commute home, and people always run up really close not clearly seeing that I'm slowing down at a pretty good clip. I know, I could step on the brake, but that undermines the whole D- and D-Auto idea. This is something that could be easily addressed in firmware.

Click to expand...

Maybe write a letter to Mercedes, tell them this is a pretty serious safety issue, maybe then they will update via firmware. This is a compliant car (probably for only three years), they are not motivated to do anything extra.

Click to expand...

True, but past 3 years they will have to have another "compliant car". That problem won't just go away.
What it takes is a lawsuit

Take comfort in this: when someone hit you from behind, it's always their fault ... ;-)

True, but then I have to wait another month or so to get new carpool stickers from the CA DMV, not to mention the hassle

phototrek said:

I don't get it: why don't the brake lights come on when the car is at maximum regen? This is the case with the Tesla and eGolf, and should be standard. Today alone I got three people gesturing at me during my commute home, and people always run up really close not clearly seeing that I'm slowing down at a pretty good clip. I know, I could step on the brake, but that undermines the whole D- and D-Auto idea. This is something that could be easily addressed in firmware.

Click to expand...

It really alarms me when people observe that this is now a problem. It shouldn't be. Vehicles have had this functionality since cars were invented. When you drive a vehicle with standard transmission and down shift, there are no brake lights and the car decelerates at a rate similar to max regen in an EV. I do it when driving on ice or slick roads b/c it gives me the ability to better control the car. Trucks do this all the time on long downhill slopes to save brakes, I guess it is just easier to see they are slowing down because they are so big.

If one is following a car with the proper spacing, such slow deceleration should not be a problem if one is paying attention to the car in front of them. Brake lights exist to warn one of sudden change in speed, unfortunately many drivers routinely use their brakes instead of coasting, causing all sorts of issues as folks behind them over-react. For some reason drivers are no longer alert enough to observe what is happening around them anymore and using something other than your brakes to slow down has become an issue. Maybe requiring cellphone jammers in cars would help...

Agree with above. I used to brake by downshifting on my Camry a lot. Never had a problem.

padamson1 said:

It really alarms me when people observe that this is now a problem. It shouldn't be. Vehicles have had this functionality since cars were invented.

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<snip>

Yes, you are right: this USED to be the case. But these days, the percentage of manual cars is minimal, and the percentage of manual cars driven with aggressive downshifting in daily stop and go is even less. I drive manual cars all the time and when I'm bouncing between 30 and 0 I am certainly not violently shifting between second and first, just to use the engine brake in order to make a statement. Just like with everything else, times change, in some ways for the worse, and honestly I don't want to be used for re-education of the driver behind me, regardless of how appropriate it may be. Yes, cell phone jammers may be great, but that is nothing other than a snarky remark. I would love the teenage girl behind me to get off Facebook, too, but I'm not her parent nor in her car to smack her. Fact is that today the brake lights are seen as "yo slow down there", and that's the message I want to communicate. Tesla, VW, and I imagine others agree. If it saves me a lengthy run to the body shop I'm all for it. Besides, the brake lights are on in "hold" mode, too, which is in the good old world just being in neutral.

Besides, it's engine braking, so I don't see it as such a far fetched thing for the brake lights to come on. Some may argue that they should have always done that, even in the good old days.

BTW, when trucks are using their engine brakes on long slopes they aren't slowing down, they're just barely trying to maintain speed, and even for that they usually have to use their compressor brakes, which do activate the brake lights. Maybe it's too hard to notice because people are going by too fast.

phototrek said:

Yes, you are right: this USED to be the case. But these days, the percentage of manual cars is minimal, and the percentage of manual cars driven with aggressive downshifting in daily stop and go is even less. I drive manual cars all the time and when I'm bouncing between 30 and 0 I am certainly not violently shifting between second and first, just to use the engine brake in order to make a statement. Just like with everything else, times change, in some ways for the worse, and honestly I don't want to be used for re-education of the driver behind me, regardless of how appropriate it may be. Yes, cell phone jammers may be great, but that is nothing other than a snarky remark. I would love the teenage girl behind me to get off Facebook, too, but I'm not her parent nor in her car to smack her. Fact is that today the brake lights are seen as "yo slow down there", and that's the message I want to communicate. Tesla, VW, and I imagine others agree. If it saves me a lengthy run to the body shop I'm all for it. Besides, the brake lights are on in "hold" mode, too, which is in the good old world just being in neutral. <snip>

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Good Point. Times have changed and unfortunately skills have too. However brake lights are only one indicator that a vehicle is changing speed, there are a whole lot more, and for some reason people no longer seem to use them.

My statement on cellphones was not about snarkiness, but on paying attention to the task at hand. If one is not observing what is going on around them b/c they are talking on the phone, playing with the radio, or texting, the only thing they are going to notice is brake lights and not that the distance between them and the vehicle in front of them is closing. When they notice, they slam on the brakes (overreact) and things cascade. I was thinking that incapacitating a phone in a EVERY vehicle as soon as the ignition is turned on would help solve that particular attention deficit disorder. Even though there have been a ton of safety improvements, too many people in the US forget that 32k drivers die annually in the US (that's 1k more than by guns), fail to realize that cars can be weapons too, and drive carelessly. Driving should be a full time task, not time-sliced.

So I now have to use my rear view mirror more, be even more alert than I used to be, and do my best to get away from crappy drivers. Oh for the days of real drivers Education where they spent time on the underlying reasons for why driving rules exist instead of just naming them so kids can ignore them.

So I did a random test and jammed in the 2nd gear at about 60mph (redline, 7k rpm) in my S4. Not something I would recommend doing in daily life, and really not something I have ever done in real life outside of the race track. In any case, that yielded a 0.21g deceleration, which surprised me. Then for comparison I put Beverly in D- and came almost to a standstill form 60mph, with a maximum deceleration of 0.13g. So there is a difference, but in real life probably not that much since most manual tranny drivers won't do what I did. Nor will I in the future