Ga. Code § 48-8-269.42
Prior to the issuance of any call for the referendum by any county that desires to levy a tax for transit projects authorized under this article, the county shall determine whether the region has proposed a referendum on a tax under Article 5 of this chapter. This determination shall be based on whether, pursuant to paragraphs (2) and (3) of subsection (c) of Code Section 48-8-245, a majority of the governing authorities of counties within the region containing the county proposing the tax have passed resolutions calling for the levy of a tax under Article 5 of this chapter. If a majority of the governing authorities of the counties in the region have passed such a resolution, the county proposing a tax under this article shall postpone the referendum under this part until the regional referendum has been decided. No ballot shall propose a tax under this article and under Article 5 of this chapter at the same election.
OCGA § 48-8-269.42