text: So The council describe the A90 as:
  
   A90From west end of Princes Street to the Forth Road Bridge.Street 
  
  https://www.edinburgh.gov.uk/directory-record/1223144/a90
  
  I believe that the signage matches this.
  
  The A8 is a tricky one, Historically, it's eastern  terminus has the East end of Princes Street where it meets the A1, A7 and A900; but since Princes Street is restricted this can't be considered as part of the A8 route. Using the On-the-ground rule, there also is no A8 signage starting in the East End of Princes Street.
  
  