In my study of numerology I have discovered that numbers never lie they always tell the truth even if you have no knowledge of numbers. We will look at the stop sign and interpret the meaning of this symbol using numerology, tarot and symbology.
What are we working with the word STOP on a RED OCTAGON FIELD.  

OCTAGON  8 sided  THE 8TH CARD OF THE TAROT IS JUSTICE *
RED      REPRESENTS MARS ENERGY AND ONE ENERGY
STOP   S     T     O     P     4 LETTERS
          1 +  2 +  6  + 7  =   16/7
Lets start at the bottom of the list and work up
7 is the number of contemplation of going with in - in this case it is telling you to pay attention the 4 is the number of physicality, red the mars energy and one energy both of action

so when you approach a stop sign the message you are getting is that there is action and force (1) of a physical (4) nature crossing your path at a perpendicular (placement of sign) angle, and you need to stop and pay attention (7), concentrate on the crossing or you will meet justice (8) in the form of an accident death loss

the numbers of     stop 1 action is meeting it's
                    opposite 2 need to be at peace
                    add love 6 and service go
                      with in  7 and concentrate
                 beware of 16 the lighting struck tower more mars energy

*I know that the Tarot lists the 8th card as strength and justice as 11th. I also believe, as others, that these two cards were deliberately switched as to hide the truth from all but the most ardent seekers and there true nature is reversed. I will discuss this in more detail when I start posting my analysis of the numbers under my Joy of Numbers title. I came to this conclusion by the study of numbers not the study of Tarot, if the original system works for you then use it, I am not asking any body to believe what I believe. Everybody is on their own path that which is right for you will be presented to you.