From: turnkey@q.com   
      
   There is, as usual, a lot of BS about the 85%.  In reality, there is no   
   stretch of highway that has been posted at a true 85%.  Why?  because that 85%   
   flow rate has been measured where there is a posted limit and presumably law   
   enforcement.   
      
   The average driver will drive at a speed he is fairly sure will not cause him   
   to get a ticket.  Usually that 85% will be about posted plus 10%.  I have   
   driven every state in the union, coast to coast, N to S. multiple times.  That   
   posted plus 10% is an    
   almost universal observation.   
      
   Several years ago, the State Patrol announced a "Emphasis patrol for speed" on   
   the major N/S highway I live on.  Posted 60, flow is, and always has been,   
   right at 65/66.  Guess what the cutoff on speed tickets (announced by the   
   State Patrol) was.  That's    
   right.  66 anything over would be ticketed.   
      
   Thus one would think that the posted should be 65.  Guess what the flow would   
   be within a month.  Yep, 71/72.  Given enough iterations of raising the posted   
   the flow would probably agree with the posted but that would have to be 80 or   
   more.   
      
   The only true 85% study would have to be on a long stretch of highway with no   
   posted limit and a public that was aware that they could drive any speed they   
   wanted.   
      
   Harry K   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)