European regulations cover it:

E/ECE/324 E/ECE/TRANS/505, Addendum 47, Regulation No. 48, Revision 6, dated June 2010.

2.28. "Emergency stop signal" means a signal to indicate to other road users to the rear of the vehicle that a high retardation force has been applied to the vehicle relative to the prevailing road conditions.

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Further investigation reveals that details for the systems are laid out as follows.

6.23. EMERGENCY STOP SIGNAL

6.23.1. Presence

Optional

The emergency stop signal shall be given by the simultaneous operation of all the stop or direction-indicator lamps fitted as described in paragraph 6.22.7.

[followed by details as to the position and number of the lights]

6.23.7.1. All the lamps of the emergency stop signal shall flash in phase at a frequency of 4.0 ± 1.0 Hz.

6.23.7.1.1. However, if any of the lamps of the emergency stop signal to the rear of the vehicle use filament light sources the frequency shall be 4.0 +0.0/-1.0 Hz.

6.23.7.2. The emergency stop signal shall operate independently of other lamps.

6.23.7.3. The emergency stop signal shall be activated and deactivated automatically.

6.23.7.3.1. The emergency stop signal shall be activated only when the vehicle speed is above 50 km/h and the braking system is providing the emergency braking logic signal defined in Regulations Nos. 13 and 13-H.

6.23.7.3.2. The emergency stop signal shall be automatically deactivated if the emergency braking logic signal as defined in Regulations Nos. 13 and 13-H is no longer provided or if the hazard warning signal is activated.

 

So basically it (brake lights/hazard lights) can flash legally but has to conform to the above.

So only on heavy braking really and it has to be at a certain rate.

 

So to have the strobe operational on a normal apoach won't be legal..
It's only legal if it happens when I'm and if I'm stopping and heavily braking?

 

Pretty much. But with the side ones being constant and not flashing you might get away with it.

It shouldn't pass a mot either.

 

Yeah it would only be the spoiler brake light. Not the normal rears... Still ileagal?

Thanks btw buddy.

 

Yeah because one of the rear lights is flashing. To flash it has to conform to the above.

I mean you might get away with using it because the side ones are solid. Like people with numberplate mods, they get away with it but it's not legal etc

 

Right "/ and do you know what the conceqwnce would be should I get pulled for it?

Obviously I know there's an MOT risk.

 

That, I have nothing specific on unfortunately.

But I imagine it would be something along the lines of defective lighting and a prohibition notice possibly?

 

Sounds pointless, put the money to something better for the car.

 

Please don't.

If I am on a motorway at night I do not want to see strobe brake lights ahead and think someone is braking heavily due to an incident.

 

^ This.

It's not legal...so just accept it and move on. Don't try and wangle around it by finding out if the punishment for fitting it is low enough to warrant fitting one.

If I saw someones 3rd brake light flashing like that and the other 2 just solid red light...I would just assume they had an electrical fault with the car.

Completely pointless.

 

OK! Point taken! "/ Jeeze!
Thanks for you help igfst

 

That would be so annoying if you were following it!

 

i have seen this on some higher car marques.....hard braking, the high brake bar strobes.....i thought the same, guy has a lecky fault, but nope, its a feature. think it was a beamer if i recall on the A9.

 

I've got Rs software on my ecu and my car does this already, hard breaking flashes the brake lights,

 

I've got Rs software on my ecu and my car does this already, hard breaking flashes the brake lights,

Do you mean it flashes the hazards? Never seen brake lights flashing on an RS :lol:

 

Is this to match your blue illuminated washer jets and chrome wipers?

 

The ST250 does it, was at the fleet driver show at silverstone this year, driven round the national track by professional drivers - other ST's, beamers etc. were flashing under heavy braking.

 

ST225 flashes hazards under heavy braking. There's a tilt switch under the bonnet which activates it.

 

Brake lights will flash in an emergency braking situation
If the brake lights were to strobe under MOT conditions, they would fail as the are operating in a manner that they are not designed to. The brake lamps should illuminate for the period that the pedal is pressed.
Would look anyway, and would serve much of a purpose