Flashing third tail light

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Truthfully, it's not that hard to find studies that suggest the a flashing brake light may be beneficial. The OEMs have studied it, and another study is the first result in a Google search.

That said, various factors, including how a system is implemented, don't validate the aftermarket modules installed by dealers and owners, and don't make them legal devices.

Mercedes' effort to legalize them in the U.S. wasn't based on hunches that any implementation of flashing lights would be effective, under any condition. Their research no doubt lead them to develop a specific implementation, with factors such as frequency, duration, speed, and deceleration taken into account. (Its system only operates under emergency braking situations, at speeds above 31 mph, and with a specific frequency and duration of flashes.)

None of which the user-set aftermarket modules take into account.

It's a concept that U.S. regulators should consider, but in the mean time, the aftermarket hacks are not compliant, their implementation almost certainly unvetted/unproven, and on a subjective level to some, obnoxious.
 
I find it interesting that the DOT hasn't approved it. I have one of the flasher modules from Kahtec (sp?) on my Hyundai Genesis and have for about 5 years now. It flashes a few times then goes solid, and takes 8 seconds to reset and flash again. If you press the brakes within 8 seconds again it won't flash, it just goes solid so it won't constantly flash. I've been pulled over before and had cops behind me, and in Texas they don't seem to care, in fact it wasn't even brought up.
 
Originally Posted By: jeff78
Originally Posted By: wag123
I am the one in this thread to point out that flashing brake lights were not DOT approved and illegal in SOME states.
Just because something is not DOT approved for inclusion by manufacturers in new vehicles does not necessarily mean that it is illegal.


The photometric requirements and behavior of brake lamps is outlined in Federal Motor Vehicle Safety Standard No. 108 - they are required to burn steadily when the brakes are applied. There is no allowance for flashing. Because it is a federal safety standard, states may not override it. In the event of a conflict ('my state's motor vehicle code says it's okay for brake lights to flash'), the state loses.

It wouldn't be much of a federal safety standard if states could override parts of it arbitrarily, would it?


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The legality of installing/using an accessory after a vehicle is manufactured is entirely up to the states.


Only if the accessory is not regulated by or in conflict to federal safety standards. For example, if you want to put a Rudolph nose on the center of your front grille at Christmas, chances are it is not going to affect the crashworthiness of your vehicle, so would not be prohibited to sell or install. However, if the Rudolph nose is one that lights up bright red, that would be in violation of FMVSS 108 and would not only be illegal but unwise for obvious reasons.

Flashing brake lamps are not legal for passenger vehicles, regardless of what the people selling/installing these modifications or your state says. I can only assume that the sellers/installers are clueless about the law - it is either that, or they are outright lying.



We had this discussion over in the motorcycle section, my post below has cites:

https://www.bobistheoilguy.com/forums/ub...mod#Post4772803

If this were true, dark window tint film (applied AFTER a vehicle is manufactured) would be illegal in all 50 states.
The bottom line is that it is the STATES that are responsible for prosecuting motor vehicle violations, NOT the federal government. The states do not have to pass a law specifically allowing a modification (and going against a DOT regulation), all they have to do is to not prosecute the violators of a federal regulation.
 
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US DOT requires that signaling devices on all vehicles conform to the same standards for obvious reasons.
There is nothing that allows any flashing brake lights on any vehicle under these federal standards, which apply always and everywhere in our country.
Hence, these are non-standard devices not approved by the feds for road use anywhere in this country.
Have another driver hit you hard in the rear when using one of these unapproved non-standard signaling devices and the offending driver would have a solid legal argument that they had no idea what a flashing light on the rear of your vehicle was supposed to mean.
Did it mean that you were braking hard or accelerating hard?
They'd have no duty to understand the meaning of an unapproved and non-standard device, nor should they.
 
Originally Posted By: fdcg27
Have another driver hit you hard in the rear when using one of these unapproved non-standard signaling devices and the offending driver would have a solid legal argument that they had no idea what a flashing light on the rear of your vehicle was supposed to mean.
Did it mean that you were braking hard or accelerating hard?
They'd have no duty to understand the meaning of an unapproved and non-standard device, nor should they.


Exactly right. Not to mention, as pointed out by somebody else, if there is an accident and your insurance company finds out you have an illegal modification to your brake lights, they will use that to deny any claim.

If I started a thread here asking how to make crack, I bet it would be locked instantly. I don't see why this is any different. Illegal is illegal, and it's not OK to discuss here.
 
I've seen blinking third brake lights on some tankers here in TX. If it was that big of a deal, the DOT cops would have already broke it off in their backside. Most cops don't care because if they came across one, it looks legit.
 
Originally Posted By: PumpPusher
I've seen blinking third brake lights on some tankers here in TX. If it was that big of a deal, the DOT cops would have already broke it off in their backside. Most cops don't care because if they came across one, it looks legit.

Unfortunately, cops have a very basic knowledge of the law. They could never be lawyers without some serious learnin'. Their job is to take you in and let the judge figure it out later...

It could possibly be legal on something like that, they have a different set of rules to follow. I wouldn't mind them on large/dangerous/unusual things - but not on a car.
 
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European manufacturers like Mercedes-Benz and Volvo have models that come with brake lights that can flash. The reason for that is that is to create a visual distinction between slowing down and an emergency full stop. In the case for some models of Mercedes, light to moderate pressure applied on the brake pedal activates the brighter mode of the tail lamps, but when it detects a sharper step as a result of the driver reacting to an obstacle (or person) on the road, the brake lights will flash.
SOURCE

Seems reasonable. And Mercedes and Volvo being top tier safety companies, I bet they know a thing or a million. The blinking with moderate to hard pressure just makes so much sense on daily commutes where riding the brake for miles on end is the norm.
 
Originally Posted By: PumpPusher
I've seen blinking third brake lights on some tankers here in TX. If it was that big of a deal, the DOT cops would have already broke it off in their backside. Most cops don't care because if they came across one, it looks legit.

That's because, in Texas...
A. A flashing 3rd brake light is not illegal by Texas law or Texas DOT rule as long as it stops flashing within a couple of seconds when the vehicle is moving, so they don't ticket for them. Only continuously flashing lights to the rear on a non-emergency moving vehicle (any color) is specifically spelled-out as being illegal. Driving down the road with your emergency flashers going is illegal here (although rarely enforced). They are tough on truckers in Texas, so if flashing 3rd brake lights WERE illegal, "the DOT cops WOULD have already broke it off in their backsides". Our Texas DPS Troupers are VERY up on traffic/vehicle laws/regulations here and they WILL stop/ticket you on virtually any infraction.
B. Since flashing 3rd brake lights are not illegal here, vehicles equipped with it WILL pass a state safety inspection.
C. If it was causing a safety concern, Texas DOT would pass a rule forbidding it and vehicles equipped with it would no-longer pass yearly safety inspections and you WOULD be subject to getting a ticket. They did this with higher wattage and/or brighter (and even off-color, like blue or purple) aftermarket headlamp bulbs (including HID and LED conversion bulbs). They also did this with dark window tint film that was too dark, multiple wiper blade conversions, and the smoking of headlamp and tail lamp lenses.
D. The main left and right brake lights MUST function normally, if they flashed upon braking the vehicle would NOT pass a state safety inspection and you would be subject to getting a ticket.
I don't think that it is a big problem or safety concern in most other states either because I have traveled all over the country with mine over the last 10 years and have never been stopped for it.
 
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Originally Posted By: fdcg27
US DOT requires that signaling devices on all vehicles conform to the same standards for obvious reasons.
There is nothing that allows any flashing brake lights on any vehicle under these federal standards, which apply always and everywhere in our country.
Hence, these are non-standard devices not approved by the feds for road use anywhere in this country.
Have another driver hit you hard in the rear when using one of these unapproved non-standard signaling devices and the offending driver would have a solid legal argument that they had no idea what a flashing light on the rear of your vehicle was supposed to mean.
Did it mean that you were braking hard or accelerating hard?
They'd have no duty to understand the meaning of an unapproved and non-standard device, nor should they.

The US DOT can NOT make/regulate/enforce traffic laws, they can only make rules regulating new vehicle manufacturing and sales. Traffic laws and the enforcement of them are relegated exclusively to the states. It is up to the individual states to regulate the legality of aftermarket devices installed AFTER vehicles have been manufactured. This is how aftermarket HID and LED headlamp conversion bulbs are able to be imported and sold in the US. Talking about dangerous, these ARE dangerous IMO, and are illegal in Texas!
Once again, I point to window tinting as an example. The US DOT regulates how dark the window tint can be on new vehicles. Many states allow darker aftermarket window tint film to be installed AFTER a vehicle has been manufactured. If what you are saying were true, this would not be allowed.
 
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You seem to be confusing state traffic enforcement priorities with federal safety standards.
They aren't the same thing and I suspect that when you actually got into a serious liability situation, federal standards would prevail.
There is also the factor of federal pre-emption in just about any motor vehicle standard you'd care to name, save for the emissions carve-outs some states are allowed.
Whether Texas thinks something is illegal or not is irrelevant.
 
Originally Posted By: wag123

That's because, in Texas...
A. A flashing 3rd brake light is not illegal by Texas law or Texas DOT rule as long as it stops flashing within a couple of seconds when the vehicle is moving


Problem is it's still federally ILLEGAL. Kind of like smoking marijuana in Oregon. Yes, the state says you can smoke marijuana, but you can still be brought up on federal charges if they decided to enforce it. There is no protection from employers, landlords, etc, for smoking marijuana.

That then goes back to the lawsuit/insurance claim problems. You will be held liable if your car didn't leave the factory with that. Same would be true for darker tint, aftermarket headlights, or anything else non DOT/OEM.

Just because there are no federal DOT cops driving around pulling people over, doesn't mean it isn't illegal, and doesn't mean it can't cause you trouble in court if something goes wrong.
 
Nobody here is going to convince me to remove the flashing 3rd brake light device I am using since I honestly believe that it is doing it's intended job, and I am obviously not going to convince any of the detractors here to install one. We will just have to agree to disagree.
To anyone else following this thread that may be considering the installation of a device like this, you should do your own research and weigh the potential benefit vs potential risk and make your decision based on weather or not YOU believe the device has merit. As far as the potential risk is concerned, I was the first poster to point out that it is not US DOT approved, but I don't believe that law enforcement (in most states) or insurance companies really care about the device's use. IMO, I believe that the benefit far outweighs the risk, particularly if you carry children in your back seat and live in a metro area with a lot of traffic congestion.
 
Originally Posted By: fdcg27
Whether Texas thinks something is illegal or not is irrelevant.

Nonsense.
THEY are responsible for enforcement.
 
Originally Posted By: lugNutz
I've heard this as being standard on some newer cars, but obviously will need to look up which ones as proof. However, my VW Passat has an "emergency braking" feature. When you brake hard, the third brake light flashes to draw attention. I had first seen this on a Hyundai while on the highway.


Pretty common in the EU. I was able to turn this feature on on the 1er. Hard braking and the brake lights will flash.
 
Originally Posted By: mightymousetech

Pretty common in the EU. I was able to turn this feature on on the 1er. Hard braking and the brake lights will flash.

Are you sure it's the brake lights and not the hazards that flash?

On wife's Q5 it's the hazard lights. I can enable/disable it using Carista.
 
Originally Posted By: wag123
Originally Posted By: fdcg27
Whether Texas thinks something is illegal or not is irrelevant.

Nonsense.
THEY are responsible for enforcement.


Not sure what you meant to convey in your reply.
If you meant to note that policing agencies in Texas haven't enforced federal standards through either ignorance or simply not considering it an enforcement priority, then we are in agreement.
That a non-standard signaling device might be legal under state law simply because there is no state statute or administrative code prohibiting it doesn't make it legal under the overarching federal standards.
 
I removed the chip that causes the third brake light to flash in my Hyundai today. It had been installed by the dealer. After reading the pros and cons in this thread, I just decided I'd rather be legal even though I doubt police know or enforce the federal law on this. I think it does get people's attention if mine is the only car with it, but if all cars had it, I doubt it would reduce rear end collisions. I haven't thrown away the chip. Perhaps I'll be convinced in the future to reinstall.

The discussion back and forth in this thread was helpful to me.
 
Originally Posted By: wag123
but I don't believe that law enforcement (in most states) or insurance companies really care about the device's use.


You think the insurance companies don't care? Have you ever dealt with an insurance adjuster? They will look for ANY reason not to pay you, even if it isn't really the cause of anything. Having illegal brake lights would be a great one if it was any sort of accident that might involve seeing your brake light. As mentioned before, even if the other party is at fault they would have a good reason to sue you because they didn't know what flashing center light means. Maybe they might not catch on that you have it...or maybe they will.

If an injury or fatality is involved, it could mean jail time. You really shouldn't mess with safety devices. If you had tinted brake lights, for example, it would be a really big deal if something happened. This is no different.
 
Originally Posted By: fdcg27
That a non-standard signaling device might be legal under state law simply because there is no state statute or administrative code prohibiting it doesn't make it legal under the overarching federal standards.

Agreed. However, if there is no STATE statute or administrative code prohibiting it, what would a Texas law officer actually ticket you for? They have to put the exact violation on the ticket. Texas law officers don't even have a minimal working knowledge of the vast number of US DOT new vehicle safety regulations, and the state of Texas is under no obligation to enforce them. Now, a cop COULD ticket you for a generic "equipment violation" if he/she KNEW FOR CERTAIN that it wasn't legal under US DOT safety regulations, but no cop that I know is going to take the time and trouble do do something like this unless the driver is being an A$$, they have bigger fish to fry.
 
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