N.J. Stat. § 32:1-121

The port authority shall, so far as it deems it practicable, treat as a single unified operation the construction, maintenance and operation of the said Midtown Hudson tunnel, the said Holland tunnel, the two vehicular bridges over the Arthur Kill, the vehicular bridge over the Kill von Kull, the vehicular bridge over the Hudson river at Fort Lee, and any other vehicular bridges or tunnels which it may construct or operate, raising moneys for the construction thereof and for the making of additions and improvements thereto in whole or in part upon its own obligations, and establishing and levying such tolls and other charges as it may deem necessary to secure from all of such bridges and tunnels as a group, at least sufficient revenue to meet the expenses of the construction, maintenance and operation of such bridges and tunnels as a group, and to provide for the payment of the interest upon and amortization and retirement of and the fulfillment of the terms of all bonds and other securities and obligations which it may have issued or incurred in connection therewith. L.1931, c. 4, s. 4, p. 20.