Ohio Rev. Code § 5555.22
The boards of county commissioners shall meet as a joint board at the time and place designated by the board of the county where the original petition is filed pursuant to section 5555.21 of the Revised Code. The time so designated for the joint meeting shall be within thirty days from the date of the filing of the petition. Such joint board shall determine whether the petition has been signed by the requisite number of landowners who are to be specially assessed for such improvement, and it shall thereupon go upon the line of the road and shall jointly act in the same manner as though the proceedings were had before a single board. A majority of such joint board may order the construction of such road, but such majority shall be composed of at least one commissioner from each county in which the improvement is located.
No person signing a petition shall be permitted to withdraw therefrom unless the joint board finds there was fraud or misrepresentation in obtaining his signature.
R.C. §5555.22