Ohio Rev. Code § 5553.16: Cost of joint improvement divided among interested counties.

The compensation and damages awarded in case of a joint improvement, together with the expenses thereof, shall be divided among the counties interested, as the joint board of county commissioners agrees and determines. In case of failure to agree on the proportion which each county is to pay, the joint board shall certify that fact to the director of transportation who shall thereupon make such apportionment.