§ 95. Proceedings by commissioner of transportation for alteration of existing crossings. The commissioner of transportation may, in the absence of any application therefor, when in his opinion public interest requires an alteration in an existing grade crossing or a change in any existing structure above or below grade, institute proceedings on his own motion for any alteration in an existing grade crossing or structure for which a municipal corporation may petition under section ninety-one, upon such notice as he shall deem reasonable, of not less than ten days however, to the railroad company, the municipal corporation and the person or persons interested, and proceedings shall be conducted as provided in section ninety-one. Notwithstanding any other provision of law the commissioner of transportation shall not, within areas which were within the jurisdiction of the transit commission on March thirty-first, nineteen hundred forty-three, order the elevation of any railroad running longitudinally on a right-of-way in, upon or along a street, avenue, highway or road without the concurrent approval of the local authorities of the city on which the railroad or such part thereof is located. The changes in existing grade crossings or structures authorized or required by the commissioner of transportation in any one year shall be so distributed and apportioned over and among the railroads and the municipalities of the state as to produce such equality of burden upon them for their proportionate part of the expenses as herein provided for as the nature and circumstances of the cases before it will permit.