N.J. Stat. § 27:7-19
The commissioner may enter into written agreement with any board of chosen freeholders or other public body, or with any person for co-operation in any work, and to assume any portion of the cost thereof. Such board or public body may raise its proportionate share of the cost in accordance with the provisions of any law providing for road improvement or maintenance.
Upon approval by the commissioner of the certificate of the inspector and engineer in charge of the work that it has been satisfactorily completed in whole or in part, according to contract, drawings and specifications, the disbursing officer of such board or body shall pay its share of the whole or partial cost to the state treasurer to the credit of the commissioner.
N.J.S. § 27:7-19