(a) The state is liable for and shall be held to pay, through its department of transportation and as other highway expenses are paid, for all rights-of-way and damages and costs incident to the acquisition and use of rights-of-way, whether by condemnation suits or otherwise as provided by existing laws, necessary to the construction of any highway, or parts of any highway, designated and adopted by the department as and for a state or state and federal aid highway in the state's system of highways.
(b) No county affected by the highways shall be liable for the rights-of-way and damages and costs incident to the acquisition and use of rights-of-way, nor shall any county pay or enter into an agreement to pay any part of the costs.