Section 81I. In a city or town having a planning board established under section eighty-one A but which has not adopted an official map no public way shall be laid out, altered, relocated or discontinued, unless the proposed laying out, alteration, relocation or discontinuance has been referred to the planning board of such city or town and such board has reported thereon, or has allowed forty-five days to elapse after such reference without submitting its report. Any city or town having a planning board established under section eighty-one A may, by ordinance, by-law or vote, provide for the reference of any other matter or class of matters to the planning board before final action thereon, with or without provision that final action shall not be taken until the planning board has submitted its report or has had a reasonable fixed time to submit such report. Such planning board shall have full power to make such investigations, maps and reports, and recommendations in connection therewith, relating to any of the subjects referred to it under this section, as it deems desirable.