159Agreements inconsistent with the provisions of this Part
(1)An agreement which purports to make provision regulating the execution of road works is of no effect to the extent that it is inconsistent with the provisions of this Part.
(2)This does not affect an agreement for the waiver or variation of a right conferred on a relevant authority by any of the provisions of this Part which is made after the right has accrued and is not inconsistent with the future operation of those provisions.