text: So, this is complicated. What do you suggest...
  
  I believe the restrictions apply to the whole of Silver Street from the junction with Queens' Road in the west to Trumpington Street in the east, (though in practice people still drive down, and access is permitted). The bollards enforce the restriction.
  
  Cycles can pass the bollards in their own segregated lanes (just a short length around the bollards)
  
  I think someone has added an additional fictitious bollard to the east of where they actually are, given where this note is pinned.
  
  Buses can pass either way at any time.
  
  Cars can, at certain times of the day drive eastbound only, westbound only or not at all. I don't think there's any time when two way traffic through the bollards is permitted. You can't derive this from a photograph or not knowing as the signs are variable (they change appearance at different times of day).