To expedite the conduct of proceedings and the making of any acquisition or improvement authorized by this part, the legislative body may, at any time prior to the appointment of a board of parking place commissioners, enter into a contract or lease with any owner or tenant of property in the proposed assessment district under which the owner or tenant, for a specified rental or other consideration and for a specified period not exceeding 20 years, reserves a reasonable proportion or number of parking spaces in a parking place of the district for the use of the owner or tenant of such property, the employees of the owner or tenant performing services on the property, and the customers of, or other classes of persons designated by, the owner or tenant and entering the property as invitees or otherwise. After the appointment of a board of parking place commissioners, the board may make such contracts or leases.