Where a public road is intersected, joined or continued by a road for which some authority other than the roads authority for the first-mentioned road are the roads authority, the following provisions of this section shall have effect.

The two authorities may enter into an agreement as to the exercise, by one, of the other’s powers under sections 41 and 42 of this Act; and any such agreement may provide for the defraying by the one of the whole or any part of the expenses incurred by the other in consequence of the agreement.

An authority shall not unreasonably refuse to enter into an agreement under this section; and if any question arises as to the terms (including terms as to payments) to be included in such an agreement, or whether an authority has unreasonably refused to enter into such an agreement, the question shall be determined by arbitration.

Any question which is required by this section to be determined by arbitration shall be determined by a single arbiter appointed, in default of agreement, by the Court of Session, or by the sheriff, on the application of either party to the question.