PHOENIX — Backers of a plan to hike state sales taxes for the next 30 years filed suit Friday because they don’t like the description to be given to voters about the ballot measure, at least in part because it spells out the size of the proposed increase.

 The lawsuit, filed in Maricopa County Superior Court, specifically objects to the Legislative Council describing the proposed levy “a 17.8 percent tax increase.’’ That, according to attorneys for the group pushing the initiative, is “misleading.’’

 But during the hearing of the council earlier this week, Stan Barnes, who lobbies for road-tax supporters, conceded the number is, in fact, ``deadly accurate.’’ What he wanted instead, however, was to describe the increase instead only as one penny on every dollar spent.

 Central to the debate is how Arizona voters perceive the issue which, in turn, could determine the outcome of the vote on Nov. 4.

 The actual language of every ballot measure is sent to the home of each registered voter. But given the complexity of many of the proposals — this one alone is 15 pages — state law requires the

 Legislative Council, made up of lawmakers from both parties, to craft “an impartial analysis’’ of each one.

 In this case, the majority of council members voted to say that approval of this initiative — dubbed “Transportation and Infrastructure Moving Arizona’s Economy’’ — would increase the state sales tax from 5.6 cents on every dollar to 6.6 cents, a 17.8 percent increase beginning in 2010.

 Approval of the measure also would hike the mining severance tax from 2.5 cents on the dollar to 3.5 cents, a 40 percent hike. Attorney Paul Eckstein, hired by initiative organizers, said those numbers showing the percentage increase, while accurate, are misleading and “calculated to cause voters to vote against the TIME Act.’’ “This expression of a percentage increase in the tax percentage would be confusing to voters, some of whom may think it means that for every dollar spent on goods they will have to pay an additional 17.8 cents in sales tax, rather than an additional one cent,’’ Eckstein wrote in the lawsuit.

 But that isn’t the only problem road tax supporters have. Barnes complained that having the first sentence of the ballot analysis talk only about the tax is not objective. He acknowledged that the rest of the analysis does explain that the monies raised would be used for the state transportation system, including interstate highway improvement projects, mass transit, intercity rail, and preservation of open space and wildlife habitats. Barnes, however, wanted all the things the levy would fund mentioned first — before any reference to the tax to pay for it — which he said would be a more objective overview. “It’s just out of balance,’’ Barnes said. What it also is, Eckstein said, is illegal because it “disproportionately focuses on the tax increases over the infrastructure improvements.’’  But Sen. Chuck Gray, R-Mesa, said there’s a good reason the tax is mentioned first: It is the only measure on the ballot that would increase taxes.  Lawmakers who are members of the Legislative Council did have an opportunity to adopt wording more to the liking of road tax supporters. Rep. Richard Miranda, D-Phoenix, offered an alternative which focused on the projects and described the proposed new tax rates without calculating for voters how much of an increase each is.

 That was rejected on a party-line vote by the panel, where Republicans outnumber Democrats.

 The lawsuit asks a Maricopa County Superior Court judge to declare the Legislative Council’s analysis invalid and bar it from being included in the publicity pamphlet being sent to voters. It also seeks a court order compelling the council members to meet again to adopt an impartial analysis.  Reports on file with the Secretary of State’s Office show that so far backers of the tax hike have collected about $700,000 for the campaign. Much of that comes from construction firms who could benefit if they get contracts for new roads or expanded light rail projects.