The department is authorized to enter into agreements with any county of this state and/or with an adjoining state or county thereof for the purpose of implementing an investigation of the feasibility of any toll bridge project for the bridging of a river forming a portion of the boundary of this state, and the adjoining state. The department may use funds available to it to carry out the purposes of this section. These agreements may provide that if any such project is determined to be feasible and is adopted, any advancement of funds by any state or county may be reimbursed out of any proceeds derived from the sale of bonds or out of tolls and revenues to be derived from the project.
RCW 47.56.042