Section 665. Tax contract by the state

It is hereby found, determined and
  declared that the authority  and  the  carrying  out  of  its  corporate
  purposes  is  in all respects for the benefit of the people of the state
  of  New  York,  for  the  improvement  of  their  health,  welfare   and
  prosperity,  and  for the promotion of their traffic and recreation, and
  that said purposes are public purposes and the project is  an  essential
  part  of  the  public  highway,  park  and  recreational  system and the
  authority will be performing an essential governmental function  in  the
  exercise  of  the  powers  conferred by this title, and the state of New
  York covenants with the purchasers and with all subsequent  holders  and
  transferees  of notes and bonds issued by the authority pursuant to this
  title, in consideration of the acceptance of and payment for  the  notes
  and  bonds  that the notes and bonds of the authority issued pursuant to
  this title and the income therefrom, and all moneys,  funds,  tolls  and
  other  revenues  pledged  to pay or secure the payment of such notes and
  bonds, shall at all times be free from taxation except for estate  taxes
  and taxes on transfers by or in contemplation of death.