The Planning Board may in any particular case,
where such action is in the public interest and not inconsistent with
the intent and purpose of the Subdivision Control Law, waive strict
compliance with these rules and regulations, and with the frontage
or access requirements specified in said law, and may, where the ways
are not otherwise deemed adequate, approve a plan on conditions limiting
the lots upon which buildings may be erected and the number of buildings
that may be erected on particular lots and the length of time for
which particular buildings may be maintained without further consent
by the Planning Board to the access provided. The Planning Board shall
endorse such conditions on the plan to which they relate, or set them
forth in a separate instrument attached thereto to which reference
is made on such plan and which shall, for the purpose of the Subdivision
Control Law, be deemed to be a part of the plan. (MGL c. 41, § 81R)