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Pulsing brake lights on new vehicles

Pulsing brake lights on new vehicles

(OP)
For many years now (say 10 or more) I have seen what appear to be brand new cars with the high-mounted brake light pulsing, while the main brake lamps do not, at a rate of maybe once per second when the brakes are applied.  This pulsing seems to stop after the cars are a month or two old, or maybe it's a mileage thing.  I've also seen some (but much fewer) relatively new cars do this, making me wonder if they were just reset, i.e., new PROM or ECU, something like that.  

Please tell me I'm not imagining this!  and what purpose it serves?  Some kind of study?  To tell you the truth, I like the idea of pulsing HM lights, but if all cars did it all the time, it would get annoying pretty quickly in heavy traffic.

RE: Pulsing brake lights on new vehicles

There was some discussion many years ago that pulsing brake lights could potentially avert some rearend collisions, by making it harder for the second driver to miss the brake light activation, perhaps as a by-product of inattention blindness.

However, whatever benefits there might have been, it's potentially swamped by the fact that people tend to use their brakes as turn signals, and often brake for no reason whatsoever.

TTFN
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RE: Pulsing brake lights on new vehicles

Brakes are for losers anyway. People who cannot anticipate or plan ahead.

Ambulance chasing lawayers would have a field day if a rear-ender cited flashing lights causing an epileptic fit as the cause of an accident.

- Steve
 

RE: Pulsing brake lights on new vehicles

In Europe, new cars with LED brake lights will pulse 5 times a second in an emergency braking situation.
This is a signal to the driver behind you that he should stand on the brake as well, instead of just "touching it lightly".
I'm not certain if the acceleration sensors are used for this, or the ABS control.

Benta.

RE: Pulsing brake lights on new vehicles

(OP)
I'm familiar with the concept of increasing pulse frequency with deceleration rate, and aftermarket motorcycle brake lights that pulse rapidly, but I've never seen anything about the OEM's running a test like this.  I was hoping someone here would have heard about it.

RE: Pulsing brake lights on new vehicles

Agree with all above - but what about having a "green" light that indicates you are accelerating and maybe a yellow light indicating you are lightly tapping the brakes??

RE: Pulsing brake lights on new vehicles

(OP)
My other question would be, since this pulsing ocvcurs when the vehicles (appear to be) brand new, how could they control the feature's turn-off?  I've looked at a Chevy wiring diagram, and I'm not seeing any connection between the HM brake circuit and the body control module.   

RE: Pulsing brake lights on new vehicles

I don't recall ever seeing pulsing brake lights on the road.

Again, it's likely that the drivers of such vehicles get complaints, and go to the dealer to get it turned off.

The other issue, particularly for somewhat older vehicles is that the top brake light was still using incandescent bulbs, which would quickly burn out with that much pulsing.

TTFN
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RE: Pulsing brake lights on new vehicles

(OP)
The behavior I recall was that on initial brake application the 3rd light would pulse, but as the vehicle slowed to a stop it would change to constantly on.  If it only did this for the first month or so of a vehicle's life I'm sure the impact to bulb life would be negligible.  It was not irritating either, because it pulsed pretty slowly.

I can't believe no one else has seen this?!  Could it have been a regional test?

RE: Pulsing brake lights on new vehicles

I saw this for the first time yesterday on a small pick-up that was not very new. I assumed it was some after market product.

RE: Pulsing brake lights on new vehicles

Funny.
This whole discussion revolves around something where nobody knows where it happens.
For all I know, the OP might be in Tasmania...
Probably, her/his observations were made in the USA, which everyone knows is the centre of the world. But perhaps not.
I posted about European cars earlier, but that was most likely irrelevant.

Well....


Benta.

RE: Pulsing brake lights on new vehicles

There was an attachment that pulsed a white strobe light in the brake light some years ago, thankfully it appears to have not cought on.
B.E.

The good engineer does not need to memorize every formula; he just needs to know where he can find them when he needs them.  Old professor

RE: Pulsing brake lights on new vehicles

(OP)
I was talking to a car parts wholesaler today and he may have the answer.  He says the local dealers were installing pulsers on new cars and newer used cars in the same fashion as they used to sell "poly razzmatazz" paint sealants for added profit.  They were charging a couple of hundred bucks for adding the module.  He said the modules rarely lasted 6 months before burning out.  That would explain why I haven't seen any older cars with them.

RE: Pulsing brake lights on new vehicles

So the answer is shonky car dealers. Whoda thought, especially in Tasmania.

benta

Although USAans are the biggest single group here, they are still well short of a majority, so you are correct to wonder what jurisdiction and traffic laws might apply. I get accused of Yank bashing and even offend some people who I hold in high regard if I suggest that some from the USA unreasonably expect us to automatically know this.

It is quite a while since GM sold anything with a Chevy badge in Tasmania, so the fact that RossABQ refereed to a Chevy wiring diagram is a reasonable indication he is not from Tasmania or anywhere else GM does not sell Chevy badged cars. I guess that leaves the Americas and the Middle East as possibilities. Maybe parts of Africa?

Anyway, problem solved, no matter where in the world he is.

 

Regards
Pat
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RE: Pulsing brake lights on new vehicles

Given that the OP has been posting with US-related topics, coupled with mentioned items rarely found outside of the US, it was a reasonable assumption that he was located in the US.

TTFN
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RE: Pulsing brake lights on new vehicles

(OP)
Benta's comment has merit.  I've seen similar comments before and should have clarified.  

I saw a piece buried in the back pages of the newspaper to the effect that a 20-year study of the impact of high-mounted brake lights on the rate of rear-end collisions in the US was... ZERO.  As I recall, the study was conducted by the Insurance Institute for Highway Safety, who had previously (before the reg's became mandatory) estimated a 50% drop in rear end collisions. Counter-intuitive, but if we were totally data-driven, wouldn't that argue for a repeal of the regulations?

RE: Pulsing brake lights on new vehicles

I expect the rise of the cell phone (& subsequent texting) with it's attendant driver distraction may have more than offset any benefit brought about by the CHMSL.

This begs the question, why not eliminate turn signals since nobody uses them anyway?

----------------------------------------

The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.
 

RE: Pulsing brake lights on new vehicles

The point of high-mounted brake lights is that you will (theoretically) see not just the brake lights of the car in front of you, but also the lights of cars further ahead (through the cabin windows).
However, as the odds are that the car in front of you will be a Ford F650 or some other monstrosity, the safety effect is cancelled.
(some sarcasm here...)

Benta.
 

RE: Pulsing brake lights on new vehicles

I don't recall seeing any "pulsing brake lights" on cars here in Socal, lately.  I have a guy on a Harley that passes me in the mornings that has a pulsing headlight and a brake light that goes amber when he backs off the throttle.  The red brake light pulses faster as he applies more brake.  First saw him several years ago.  The brake light deal, amber/red, sounds doable for a car, the pulsing headlight kinda bothers me, though.

Rod

RE: Pulsing brake lights on new vehicles

I have also seen evidence that improved dynamic safety features in a car end up reducing travel time rather than decreasing accidents as drivers readjust to the same safety margin. I think the dat was to do with ABS.

Certainly more distractions and a fashion statement of heavy window tints counters some safety devices.  

Regards
Pat
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RE: Pulsing brake lights on new vehicles

Pat:

I pump the brake pedal whether the guy behind me is awake or not.  We were hit from behind (notice I did not say rearended here) back in '77 by a person doing 55 when I was stopped.  Do not want to go thru that again.

Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
 

RE: Pulsing brake lights on new vehicles

Mike, I've also had the misfortune of being whacked by an errant Chrysler while sitting at an intersection in Long Beach in my little Lotus Cortina.  The only saving, such as it was, was that I was sitting with the car in gear waiting for the light to change when I saw this giant three ton 'turd' coming at me.  I launched my car like at the drag strip.  Still hit me but the impact was mitigated a bit by my efforts.  Still totaled a very expensive little car and GEICO  needed several years and a good bit of prompting from the courts to pay their share which was nowhere near enough.

I'm with you.  Not something I need to repeat.

Rod

RE: Pulsing brake lights on new vehicles

I got rear-ended in the return line of a rental company.  Pumping the brake wouldn't have mattered, since that person was busy rummaging around for the rental agreement instead of watching where they were going.  Sometimes, you cannot escape your fate.

TTFN
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RE: Pulsing brake lights on new vehicles

I'm rethinking my braking behaviour. Even though I think that brakes are for losers with no forward planning (unless in racing conditions), should there be a "I'm off the gas indicator"?

- Steve
 

RE: Pulsing brake lights on new vehicles

(OP)
5 years ago I was 4th or 5th in line at a stoplight that had just turned green, in th emiddle of three lanes.  I had just taken my foot off the brake, and was just barely moving.  I was in a Chevy C1500 exteneded cab longbed that weighed 5600#.  A guy slammed into my rear at 40 mph in a Grand Cherokee, because he was busy dialing his cell phone to notice I wasn't moving, there were no brake lights lit on any of the cars.  My truck was old enough that it did not have headrests, so my head snapped back completely horizontal. 5 years later my neck is finally pretty normal. (BTW, he had a suspended license due to multiple DUI's, no insurance, no registration, and was unemployed)

No fancy safety features would have done as much as a simple headrest.  Although a collision detection system that fired a rocket propelled grenade into his Jeep sounded pretty good at the time.

RE: Pulsing brake lights on new vehicles

That wouldn't have mattered to some degree.  By the time a targeting system decides that the car is, in fact, a threat, the RPG would detonate too close to your car, and the remaining bits of the OPFOR would still be coming at you only slightly slower, albeit, with less damage potential.  

A transporter beam would be way more useful.  Your guy could have been dropped off in Timbuktu or similar.

TTFN
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RE: Pulsing brake lights on new vehicles

(OP)
Don't discount the personal satisfaction aspect..

RE: Pulsing brake lights on new vehicles

Since we're already somewhat off-topic from the original question, and some general discussion of brake lights has begun:

An accident a few years ago makes me think that, yes, something less crude than brake lights would help. On a rainy night my son was following another car as they approached a curve (familiar to both drivers). Out of view of my son, a dog ran in front of the other car- whose brake lights had already been lit for awhile. No car occupants (nor the dog) were injured in the ensuing collision, nor was there much vehicle damage. But I imagine that some type of "decceleration signal" might have helped avoid this collision.

RE: Pulsing brake lights on new vehicles

... 'deceleration'... should have used spell-check!

RE: Pulsing brake lights on new vehicles

Quote (pontiacjack):

. . . whose brake lights had already been lit for awhile . . .

That right there is part of the problem.  When somebody uses the brake to modulate speed to down around the ±1 mph level, to control following distance to ± a foot or two, or needlessly rests their foot on the brake pedal going through a curve instead of getting slowed down the necessary amount first - a following driver isn't going to immediately know when the leading driver suddenly gets serious about stopping.  

Whether pulsing brake lights above some threshhold would be a real solution or just a temporary one until people start disregarding the steady brake light illumination is a separate matter.

It's a lot easier to trust the driver who uses the brakes harder but only when stopping or slowing significantly.

I'm sure that in addition to operator inexperience in this specific case, consumer transmission preference and mandated efforts at reducing fuel usage deserve some share of the blame.


Norm

RE: Pulsing brake lights on new vehicles

There is the "nothing new in the automotive world" aspect in all this. It seems all this anti collision, brake light "whatever" has been done several times by various well intended individuals/companies. The high mounted brake light, 1930's, the pulsing brake light, 1940's, the amber deceleration light, 1950's, etc, etc. I had a neighbor that drove a '38 Buick with a system of red, green and, amber lights arranged across the rear window. Green, on the power. Red, brakes. Amber off the throttle... and that was in the mid 50's. I still see the dude on the BMW that has a pulsing brake light, faster the harder the application of brake. I have not seen any (thankfully) pulsing headlights lately, though.

I've mentioned that I live a few blocks from a high school and that means I get to see possibly a bit more troublesome driving/texting/phoning/horseplay/giggling inattentive driving habits. None of which would be mitigated even one tiny little bit by any of the "brake light solutions" spoken of in this thread. Hell, I nearly got creamed by a teen that was turned completely around facing the back seat!!!

Rod-----gettin' too old for this crap.

RE: Pulsing brake lights on new vehicles

"I have not seen any (thankfully) pulsing headlights lately, though."

There's some kind of bikes (BMW maybe? Others?) that have pulsing headlights. Very annoying. I'm sure the intent is to "enhance visibility", but there are times that I wonder if oncoming drivers wouldn't fixate on the pulsing light and plow right into them.

RE: Pulsing brake lights on new vehicles

I think all the pulsing motorcycle headlights are aftermarket addons.

----------------------------------------

The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

RE: Pulsing brake lights on new vehicles

Or faulty voltage regulators...

Benta.

RE: Pulsing brake lights on new vehicles

The driver's handbook of my recently acquired 2008 Volvo S40 D5 (UK model) says if the ABS activates, the brake light pulses.

So far I've only managed to try out the ABS once and that was when a large hare ran out from the hedge at 5:45 a.m on a single track road. Just missed it, by a hare's breath (yes, I know that's not the actual saying, but ..).

There was no-one else stupid enough to be driving to work that early so there are no evidential reports from following drivers, to say if it did pulse, or not.

RE: Pulsing brake lights on new vehicles

Which is of smaller dimension:
>hare's breath, or
>hair's breadth?
I just want to be sure to use an expression appropriate to its context...

RE: Pulsing brake lights on new vehicles

I think an RCH is smaller than both.

- Steve

RE: Pulsing brake lights on new vehicles

Smallest measurement round these parts is a gnat's c**k.

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