Trafficators had actually been around since the early 1900s and existed until around the 50's in the UK and Europe, often the 'flag' would stick, which required a thump on the door pillar to 'encourage' it to open!
Max..

 

Now I am wondering about the second part of the question, are you only using a total of three stop lamps? Or are you using three on each side? Would you please clarify that for me.

i'm using 3 led strips (21 smd per strip) per stoplight, will be doing 2 separate circuits for watch stoplight, but already have the position signal, turn signal and reverse lights .. so from that schematic i'm not taking into consideration the turn signal connection to it, thats why i was asking if there is anything to remove from the schematic considering i dont want the stoplights being afected by the turnsignal,i just want them to turn on progresively and fast (that 100 ms is great) when i hit the break.

 

X OK, now to the question of what to do to use the circuit to only drive three stop lights. The circuit diagram shows driving dual lights because that is what the car mentioned had. If you connect your three stop lights instead, that is all the change needed. Also, whatever mosfets you had originally selected as shown in post #1 should work quite well.
And if you are unable to locate a CD4528, a CD4538 will also work, as well as an MC14538. At least I think that is the number of the Motorola equivalent. That particular device is produced by a number of companies. You do need to be sure that the supply voltage never gets above 15 volts, that is the one limiting requirement of this circuit.