Critics of the multibillion-dollar transportation measure the Metro Council referred to the November ballot last month are challenging the proposed ballot title.

Opponents filed the legal challenge in Multnomah County Circuit Court on July 31.

"Metro's proposed ballot title is insufficient to satisfy the requirements of ORS 250.035(1) because the 10-word caption fails to reasonably identify the subject of the measure, the 20-word question fails to plainly phrase the chief purpose of the measure, and the 175-word summary fails to concisely and impartially summarize the measure and its major effect," the petition for review says. "As a result of these deficiencies, the ballot title is not concise and it is unfair."

Opponents of the measure filed both the challenge and an accompanying memo explaining what they believe are the shortcomings of the language Metro proposed.

In effect, the opponents allege, Metro is seeking to levy a 0.75% tax on payrolls of employers of 25 or more workers (except for state and local government agencies) but does not explicitly describe the taxing mechanism in the proposed ballot title.

"What Metro's measure proposes is a wage-based payroll tax," opponents say in their filing. "Metro's ballot title instead uses the term 'business tax' in an apparent attempt to make its proposal more palatable to voters. But Oregon law does not permit a measure's proponents to inaccurately represent a measure's effects for political advantage."

The memo also argues that Metro, which only added the exemption for state and local government agencies on July 16, without any fiscal impact analysis, is hiding the ball from voters in terms of costs.

"[Metro's] ballot title presents voters with a litany of transportation projects and asks the voters to fund them through a 'business' tax, but it conspicuously omits any mention of how much that payroll tax will raise in order to do so," the filing says.

Ballot title challenges are common in high-stakes measures. In this case, the opponents have hired the Harrang Long law firm and, specifically, Bill Gary, a former Oregon solicitor general and No. 2 official at the Oregon Department of Justice.

Metro declined to comment.