(a) An authority and the State Highway Commission are authorized to enter into arrangements or to enter into agreements, as may be determined by them to be necessary or desirable for:
(1) The investigation and study of any proposed tollway project;
(2) The use of State Highway Commission engineering and other forces, including consulting engineers and traffic engineers;
(3) The purpose of effecting such study; or
(4) The obtaining and use of outside engineering and traffic and other expert studies; all as may be necessary or desirable in connection with a proposed tollway project, with all expenses in connection therewith, which are paid by the State Highway Commission, to be deemed part of the project costs.
(b) Upon the sale of bonds all such expenses incurred by the State Highway Commission are to be reimbursed to that commission out of the proceeds of the bonds.