Section 3. Classification of highways

Highways are hereby divided into five
  classes.
    1. State highways are those constructed or improved under this chapter
  at  the  sole expense of the state, including the highways specified and
  described in sections three hundred and  forty  and  three  hundred  and
  forty-one  of  this  chapter  and acts amendatory thereof, including the
  highways  heretofore  classified  or  referred  to  as  county  highways
  elsewhere  in this chapter and heretofore constructed or improved at the
  joint expense of  state,  county  and  town,  or  state  and  county  as
  heretofore provided by law.
    2.  Controlled  access  highways  are  those  state highways which are
  entirely or partly constructed, reconstructed or improved at a  location
  where  no  public  highway theretofore existed and to and from which the
  owners or occupants of abutting property or of any other  persons  shall
  have  no right of access either as pedestrians, as operators of vehicles
  or in any other capacity, excepting at junctions of such  highways  with
  other public highways, and also excepting as such access may be reserved
  pursuant  to  the  description and map of the property which has been or
  which hereafter shall be acquired in accordance with  this  chapter  for
  the purpose of such controlled access highways.
    3.  State  thruways  are  those  highways  specified  and described in
  section  three  hundred  forty-nine-a  of  this  chapter,   constructed,
  improved or reconstructed as provided in such section.
    4.  County roads are those roads constructed, improved, maintained and
  repaired under article six of this  chapter  and  roads  constructed  or
  improved  under  a  general  or special law, which are maintained by the
  county.
    5. Town highways are those constructed, improved or maintained by  the
  town  with  the aid of the state or county, under the provisions of this
  chapter, including  all  highways  in  towns,  outside  of  incorporated
  villages  constituting  separate  road  districts which do not belong to
  either of the two preceding classes.