Ind. Code § 8-23-2-14

Sec. 14. The department may furnish on request of a county or municipality engineering service or consultation and extend the facilities of the department's testing laboratory for the testing of highway construction and maintenance materials or for any other highway purpose. When those services are rendered by the department, the county or municipality requesting and receiving the services shall reimburse the department to the extent of the actual cost of the service including salaries or personal services. When payment is made to the department by the county or municipality, the department shall receipt the payments into the accounts or appropriations from which the expenditures were made by the department in providing those services.