Backoff XP - mode 1 or mode 2?

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About to install the Backoff XP that I purchased last year. I'm trying to decide between mode 1 and mode 2. The modes are defined as follows:

Mode 1:
4 short break light flashes, followed by 1 long flash - repeats the cycle as long as the brake is on.

Mode 2:
5 quick flashes, followed by a steady on - stays steady on as long as the brake is on.

I'm leaning towards mode 2.
 
Mode 2.
The flash to get attention that you are starting to brake then constant to indicate braking is happening.

The cycling flashing would be confusing to many if you were using the brake for a longer time slowing down.
 
^^^ Yep, Mode 2 ... Mode 1 would probably confuse people.
 
Install completed. I also completed the install with the led light kit on my Givi top box. Massive difference in brake visibility.
 
Originally Posted By: David_g
I'd be surprised if Mode 1 is legal here.


Flashing brake lights are not legal in the US at all*, although you probably won't get pulled over for it unless your brake lights are doing something very annoying like constantly strobing rapidly and the officer behind you is having a bad day.

That said, there has been substantial research into this over the years that indicates that a brief period of flashing at a certain frequency may reduce reaction times for the following driver. But that's not likely to be helpful if he's staring at his cell phone.


* - on a federal level. FMVSS 108 says brake lights must glow steadily when braking, so you won't find any vehicles that roll off the showroom floor with flashing brake lights. But they can't control what you do with your car or bike after you buy it. Ultimately, enforcement is up to your local authorities.
 
Last edited:
Mode 2. If I’m stopped at a light and a car approaches from behind I’ve gotten into the habit of flashing my brake light several times via the front brake lever to draw the approaching drivers attention so they will see that I’m stopped. Especially at night.
 
Originally Posted By: jeff78
Originally Posted By: David_g
I'd be surprised if Mode 1 is legal here.


Flashing brake lights are not legal in the US at all*,

Doesn't FMVSS only regulate new vehicles, and importing of used ones? Things like brake light flashers are ordinarily regulated by state vehicle codes.

California Vehicle Code 25251.5.c Allows flashing then steady on for brake lights. It doesn't allow either of the two modes in the first post, but mode 2 is closest to what's allowed here.
 
Originally Posted By: David_g

Doesn't FMVSS only regulate new vehicles, and importing of used ones? Things like brake light flashers are ordinarily regulated by state vehicle codes.

California Vehicle Code 25251.5.c Allows flashing then steady on for brake lights. It doesn't allow either of the two modes in the first post, but mode 2 is closest to what's allowed here.


No, states may not implement regulations that are in direct conflict with the FMVSS. That's as it should be - it wouldn't be much of a safety standard if states could arbitrarily override parts of it.

http://www.candlepowerforums.com/vb/show...l=1#post4630105
 
Originally Posted By: jeff78
Originally Posted By: David_g

Doesn't FMVSS only regulate new vehicles, and importing of used ones? Things like brake light flashers are ordinarily regulated by state vehicle codes.

California Vehicle Code 25251.5.c Allows flashing then steady on for brake lights. It doesn't allow either of the two modes in the first post, but mode 2 is closest to what's allowed here.


No, states may not implement regulations that are in direct conflict with the FMVSS.

I quoted the section on the California Vehicle Code that allows brake light flashers. You're welcome to tell the that they may not do that. I'm sure we're not the only state that allows them.
 
Originally Posted By: David_g
I quoted the section on the California Vehicle Code that allows brake light flashers. You're welcome to tell the that they may not do that. I'm sure we're not the only state that allows them.


I'm sure you're right. And those states' permissiveness would be as null and void as California's.

From FMVSS 108 (https://www.ecfr.gov/cgi-bin/text-idx?node=se49.6.571_1108):

S4 Definitions
Stop lamps
are lamps giving a steady light to the rear of a vehicle to indicate a vehicle is stopping or diminishing speed by braking.

Also see Table I-a - Required Lamps and Reflective Devices
Stop lamps - Steady burning. Must be activated upon application of the service brakes.


Since flashing is not 'steady burning', there is no allowance in FMVSS 108 for flashing stop lamps (brake lights). Thus California Vehicle Code 25251.5.c is in direct conflict.

Federal laws and regulations trump state laws and regulations when there is a conflict. (Google: federal preemption)

Specific cite: 49 U.S. Code 30103(b)(1) (https://www.law.cornell.edu/uscode/text/49/30103)
'Preemption — When a motor vehicle safety standard is in effect under this chapter (301 - Motor Vehicle Safety), a State or a political subdivision of a State may prescribe or continue in effect a standard applicable to the same aspect of performance of a motor vehicle or motor vehicle equipment only if the standard is identical to the standard prescribed under this chapter. '



So, to sum up flashing brake lights:

Illegal in the U.S.? Yes, regardless of what your state says.*
A good idea? Maybe.
Will a NHTSA SWAT team hunt you down for having one? Probably not.



* - I believe the lighting behavior on emergency vehicles is not federally regulated so the state/local authorities have full control over what is allowed
 
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