TAMPA — The proposed half-cent sales tax to fund Hillsborough County's transportation needs finally landed a key endorsement: the business community.The Greater Tampa Chamber of Commerce, the largest business chamber in Hillsborough, on Thursday endorsed the half-cent option that is projected to raise $117.5 million a year to pay for hundreds of projects for those who drive, bike, walk and use the bus."The cost of doing nothing is greater than the cost of investing in our transportation options," said chamber president and CEO Bob Rohrlack. "We cannot continue to ignore this. It's impacting workers getting to work. It's impacting our quality of life.''More than 60 members of the chamber's board of directors attended Thursday's vote, Rohrlack said, and it was unanimous. No one spoke against the plan or abstained from voting."When they were done voting, they applauded," he said. "It's a strong position for us to take. We're stepping up and saying this is what's right for the community."Bill Carlson, a Tampa public relations executive and one of the leaders of the opposition to the half-cent sales tax proposal, said the chamber didn't hear any dissent because it didn't ask the other side to speak."I'm disappointed that they were afraid to let their members hear the truth about Go Hillsborough," said Carlson, who prefers a 30-year plan funded by a one-cent tax. Carlson is president of Tucker Hall, though the PR firm is not involved in the project and he said he is speaking as an individual.Rohrlack said the chamber heard from voices for and against the tax plan.Thursday's vote represents the first time the business community has taken a strong position on transportation funding after months of standing on the sideline. Last week the chamber released the results of a poll it commissioned that showed residents are sick of congestion but are divided over whether they would pay a tax increase to alleviate the problem.The Hillsborough County Commission has yet to decide whether to put the sales tax referendum on the November ballot, and appears split 3-3 over the issue. Commissioner Victor Crist is considered the swing vote. However, commissioners this week unanimously approved a list of $905 million worth of transportation projects to tackle in the first 10 years of the tax if it's approved by voters.The commission followed that with another unanimous vote Thursday to draft an ordinance that would dedicate, for the next 3½ years, half of all growth in county property tax revenues to transportation. After that, one-third of future growth would be earmarked for roads, bridges and transit.That money would supplement whatever comes in from a tax increase, but commissioners hope it also signals they're willing to make sacrifices to help fix the gridlock here. Typically, a chunk of those funds pay for pet projects in each commissioners' districts.The chamber wanted to signal its support to the commission now, Rohrlack said, in advance of the April 27 public hearing on the half-cent option, which will be followed by a commission vote. The chamber said it will speak out in support of the tax at that meeting.But Carlson said the chamber is throwing its weight behind a proposal that doesn't go far enough to address the county's needs."How can the chamber members react to a plan when there is no plan; it's just a list of projects?" Carlson said. "Really what they're being asked to approve is a blank check for the county and cities to do what they want."Tampa Mayor Bob Buckhorn, one of the sales tax plan's staunchest supporters, said the chamber made the right call at the right time."The vote's going to be next week, and this is all about peaking at the right time," he said. "So I think that declaration today tells the county commission exactly where the business community is on this issue. They want it on the ballot. They recognize that it's got to be 30 years, and nothing less than 20, and that's a good thing. Hopefully, the commission will do the right thing and put it on the ballot and let the voters decide."The half-cent option is for 30 years, but the chamber specifically endorsed a tax for at least 20 years. That rules out support for Commissioner Kevin Beckner's 10-year-plan. Buckhorn spent about an hour Thursday meeting with Beckner, who asked to learn about the city's plans for its share of the funds raised by the half-cent option."Getting the business community behind this effort is going to be really important," Buckhorn said. "They're the ones that are creating the jobs. They're the ones that are expanding their companies. They're the ones that are creating opportunities. They understand every day the impact of not dealing with this.''After the vote, Rohrlack said he told chamber members their vote was the start of their support of the half-cent plan, not the end. If the commission puts the sales tax on the 2016 ballot, then the chamber and its members will have to publicly campaign for it in the fall."If we're going to take a position on this,'' he said, "everyone needs to be involved personally and everyone needs to be involved corporately to explain to the county why this is important, why it needs to be on the ballot and why it needs to pass in November."