Safer brake lights

[Steverino]

Now that we have covered adding extra lights for not racing to a stoplight and jamming the brakes, what kind of signal should we add when we don't *accelerate* at a rate that the guy behind expects? This seem to be an equal safety issue, just under opposite conditions.

Perhaps a khaki green light? So red is stop, yellow is not accelerating (slowing down), kahaki green is accelerating at less than max speed, green light for faster than turtle start but not bat out of hell, and no lights equals "bat out of hell".

[Cord]

Let's first make sure a car on a big hill rolling backwards makes the back up light come on.

[solar_dave]

Let's first make sure a car on a big hill rolling backwards makes the back up light come on.

Don't forget the reversing beeper!

[cmr]

standard shift cars don't turn on brake lights when you are down shifting... i don't understand all of the attention this topic has received from posters on this forum...... leads me to believe most on this board never owned manual transmission automobiles before. down shifting/engine braking has been a part of driving since the beginning of automobiles/motorcycles.

[baragona]

I'm quite surprised at the vocal opposition to the idea. This really is a safety issue

This is no "more" of a safety issue than what you experience with manual transmissions.

There are always those that believe if you could pass enough laws and make enough technical innovations that we will "never" have another accident.

As far as GM going the extra mile for safety... There are $500,000 automobiles with manual transmissions that don't have this modification. Why should a $40,000 Volt be required to have it?

The "opposition" to this is because modifications cost "money". If GM adds this feature and the price of the Volt goes up to $45,000 would that be acceptable?

And finally..... Since no one has actually been rear ended yet in a Volt due to driving in "L" after 70 million miles..... How high should this be on GM's list of priorities????

[Slapshot28]

Sure, regen is a braking system, just not the Service Braking System.
Service brakes are pedal operated normally, and regenerative brakes are considered auxiliary braking systems.

The relevant paragraph that refers to regen brakes and the stop lights is 5.2.22.4 which lists deceleration limits for regen. Below 0.7M/s/s (Meters per second per second, or per second squared) the requirement is for no stop lights. Between 0.7M/s/s and 1.3M/s/s stop lights are optional, "The signal may be generated". Above 1.3M/s/s stop lights are required, "the signal shall be generated", i.e. stop lights should be lit.

If you research the deceleration provided by L, you should find it is less than 1.3M/s/s for sure, else we would have brake lights already.
(Anyone with the actual #'s?)

Whether it exceeds 0.7M/s/s is the question, but the requirement for stop lights is only for the service brakes and/or aggressive regen above 1.3M/s/s.

There are several online acceleration/decelleration calculators, like this one: http://www.smartconversion.com/unit_...alculator.aspx

I did a very quick and dirty test here at the beach, where it is perfectly flat. In Low gear with my foot off all pedals, it took 12 seconds to decellerate from 50 mph to 30 mph (maximum regenerative braking). This equates to 0.7 m/s/s, right at the bottom of the range for discretionary illumination; or if you prefer, the top of the range where illumination is disallowed. That rate of decelleration may in fact not be as much coincidence as design by GM engineers. They may have anticipated this debate, and decided to play it safe, and go with relatively mild decelleration. As many here have pointed out, LOTS of vehicles decelleration at this rate, without Stop Lamp illumination.

As a final notion, I wonder if there is a high correlation between Volt owners who prefer D over L, and Volt owners who worry about brake lights. If that correlation is high, then I agree with WOT, put your Volt in Drive, use your brake pedal as you like, and be happy!

[volt3939]

There are several online acceleration/deceleration calculators, like this one: http://www.smartconversion.com/unit_...alculator.aspx

I did a very quick and dirty test here at the beach, where it is perfectly flat. In Low gear with my foot off all pedals, it took 12 seconds to decelerate from 50 mph to 30 mph (maximum regenerative braking). This equates to 0.7 m/s/s, right at the bottom of the range for discretionary illumination; or if you prefer, the top of the range where illumination is disallowed. That rate of deceleration may in fact not be as much coincidence as design by GM engineers. They may have anticipated this debate, and decided to play it safe, and go with relatively mild deceleration. As many here have pointed out, LOTS of vehicles deceleration at this rate, without Stop Lamp illumination.

As a final notion, I wonder if there is a high correlation between Volt owners who prefer D over L, and Volt owners who worry about brake lights. If that correlation is high, then I agree with WOT, put your Volt in Drive, use your brake pedal as you like, and be happy!

Thanks for the number, just what I was expecting.

I agree, if you want stop lights, use the brake pedal.

[jeffhre]

True. And brakes are used for what? To slow or stop a moving vehicle.

I'm learning all the time. Since I first learned to drive on a non synchro mesh manual transmission, I've learned a lot about <del>brake lights</del> <ins>human nature</ins>!

[QB 45]

I think we should be less dependent on nanny technology and more so on common sense. Although, that could be the inherent flaw...

[VoltageDrop]

I think we are trying to make a mountain out of a molehill.....I LOVE driving in "L" .....you don't have to completely take your foot off of the "go pedal" all at once....what I do (and I am sure what many others here on the forum do who drive in "L") is that I "control" the degree of regeneration by controlling the release of my foot off of the "go pedal" when I am concerned the idiot behind me is too close and may cause a problem.........in this way....you won't feel like you are going to get hit all of the time........when no one is behind me.....I could just completely remove my foot off of the pedal for maximum regen and slowing down......in this way.....have never felt I was going to get hit...........

On another note.......after a bit of thought.....I too am of the camp that would be against the brake lights coming on in regen.....I have had the honor of being behind people whose brake lights illuminate every 2-5 seconds for no odd rhyme or reason....and HOW ANNOYING IS THAT..... you eventually go around and are on your merrier way...but can you imagine yourself behind your VOLT every time you realease the accelerator for any reason and the brake lights are going on or off......I wouldn't mind quick flash of the brake light (by the nanny patrol) when you are in regen AFTER a few seconds or so....but not right away.....just my $0.02