As used in this and the following sections of this article, the word "bridge" shall be deemed to include all property, rights and franchises relating thereto, including approaches; the word "improvements" shall mean such repairs, replacements, additions and betterments of and to a bridge acquired by purchase as are deemed necessary to place it in a safe and efficient condition for the use of the public, if such repairs, replacements, additions and betterments are ordered prior to the sale of any bonds for the acquisition of such bridge; the term "cost of bridge," as applied to a bridge to be acquired by purchase, shall include the purchase price, cost of improvements, financing charges, interest during any period of disuse before completion of improvements, and all other expenses, including legal fees, trustee's fees, traffic estimates and other estimates, which are necessarily or properly incidental to the acquisition or the improvement or the financing; the term "cost of bridge," as applied to a bridge to be constructed, shall embrace the cost of construction, the cost of all land, property, rights and franchises acquired which are deemed necessary for such construction, financing charges, interest during construction, and all other expenses, including legal fees, trustee's fees, traffic estimates and other estimates, which are necessarily or properly incidental to the construction or acquisition of the necessary land, property, rights and franchises or the financing; the word "commission" shall mean the state bridge commission created by this article, or, if said commission shall be abolished, any board or officer succeeding to the principal functions thereof or upon whom the powers given by this article to said bridge commission shall be given by law; the term "owner" shall include all individuals, incorporated companies, societies or associations having any title or interest in any bridge properties, rights or franchises to be acquired.