I always wonder about how we got to the standard of road lane width.
As far as I have experienced, these have almost rarely been respected (such a waste of paint on the floor) since drivers (which I have witnessed so far) manage always to neglect the separation lines and manage to fill the road to its exact capacity.
Of course you have guessed, this epiphany happened to me during my daily suffering in road traffic.
Summarizing the numbers, I managed to see a pattern.
|The demonstration by observation|
N = L + FLOOR(L/2) where N is the effective number of car lanes, L is the number of lanes drawn and L >= 2
|The formula applied in practice (L=3)|
For the meantime, I will be satisfied with this demonstration. I will be also preparing another demonstration by mathematical induction (just for the sake of being scientific, and to please my geeky self).
Your comments, counter examples or questions are mostly welcome :-D
As Archimedes said "Eureka!" (don't try to imagine me running bare-naked shouting that).
P.S. Make sure you stay civilized and ignore the usage of this Formula while driving.
[UPDATE: Demonstration by Mathematical Induction]