N.J. Stat. Ann. § 27:15-1.5

In any case where any such State aid is to be expended for the construction of any municipal road between curbs and gutters, where such curbs and gutters have heretofore been laid at the cost of the municipality and are in existence at the time the schedule referred to in section two hereof is filed, the State shall participate, within the limits of such State aid herein prescribed, in the entire cost of the construction of the road between the gutters regardless of the width thereof.