An opponent of Cobb County’s transit referendum says the county is violating state law by showing an “obvious bias” in favor of the ballot question.

Lance Lamberton, the founder of the Cobb Taxpayers Association, filed an ethics complaint against Commissioner Lisa Cupid this week, saying that as chairwoman of the board, she is responsible for ensuring the county does not use public funds to support the referendum. If approved, the referendum would authorize a 1% sales tax for the next 30 years to pay for transit and transit-related projects.

“There can be no doubt that the content of the videos and printed material clearly and indisputably advocate in favor of the M-SPLOST’s passage,” Lamberton wrote in his complaint.

As an example of the county’s alleged advocacy, Lamberton cited a flier that states “this initiative seeks to improve the county’s transit infrastructure with a focus on safety, flexibility, and reliability tailored to meet the specific needs of our growing community and local economy.”

The complaint does not detail any individual statements or actions by Cupid in support of the referendum but alleges that as the highest elected official in the county, she must prohibit county staff from violating state laws that prohibit using public money for advocacy.

“I look forward to overcoming this meritless complaint,” Cupid said.

The Cobb Board of Ethics has 60 days in which to hold a hearing on the complaint.

The board met Wednesday and appointed Marietta attorney Darrell Sutton to investigate the complaint. The board’s regular counsel recused himself.

This is the second complaint filed by Lamberton over the referendum. He filed an ethics complaint against Matt Stigall, a transit proponent who sits on the county’s Transit Advisory Board last year.

That complaint was unanimously dismissed.