N.J. Stat. § 40:72-1.1
Any municipality, which is governed by a board of three commissioners may provide that two additional commissioners shall be elected at an election to be held on the second Tuesday in May next; provided, that a proposed ordinance increasing the number of commissioners from three to five was first submitted to the board of commissioners by petition signed by electors of the municipality equal in number to 15% of the votes cast at the last general election, held for the election of all the members of the General Assembly, requesting that said ordinance be submitted to the vote of the people.
The signatures, verification, authentication, inspection, certification, amendment and submission of such petition shall be the same as for petitions to recall commissioners. Upon the filing of said petition and certification of the same by the municipal clerk the board of commissioners shall submit said ordinance without change to the vote of the electors of the municipality at the next general election. Said petition shall be filed and certified to by the municipal clerk at least 60 days before the general election at which the proposed ordinance shall be submitted to a vote of the electors.
N.J.S. § 40:72-1.1