TAMPA — Hillsborough County's new sales tax hikes for transportation and schools don't kick in until Jan. 1.But even before the first penny is collected, the state is projecting that the taxes will bring in more money than voters were led to expect when they approved the two measures Nov. 6.The Florida Department of Revenue estimates that the one percent tax for transportation will bring in $302 million in 2019, $26 million more than the estimate county officials used when they approved ballot language for the initiative. In addition, the half-percent tax that voters approved for school repairs and construction is now expected to raise $151 million in 2019, about $13 million more than first projected by the school district. The increases reflect Florida's booming economy. Statewide, sales tax revenues in September —the most recent compiled — were almost $180 million more than in the same month last year. Similar increases earlier in the year led Department of Revenue officials to increase the revenue projections that it provides to help local governments budget for the upcoming year.If the trend holds, it could mean repairs on failing air conditioners and leaky roofs at the county's schools will happen sooner. "Certainly a robust economy could generate more spending and could increase the overall amount collected," said Hillsborough County Schools spokeswoman Tanya Arja. "If we collect more revenue, we will assess immediate needs and we have the ability to move up projects."The extra $26 million for transportation would be split among Hillsborough County, Tampa, Temple Terrace, Plant City and the Hillsborough Area Regional Transit authorityHART would be the biggest beneficiary, with additional revenues adding up to $12 million. Under the county charter change that voters approved, HART must spend 65 percent of the money on buses and 35 percent on mass-transit."If this is the situation, it's obviously good news for transit," said HART interim CEO Jeff Seward. "We need to kick-start the planning process into high gear." The agency is already making plans to increase bus frequency on five routes during 2019 with 30 new buses and about 60 additional drivers.Just how much money the two taxes will raise over their lifetime is more difficult to project since estimates must allow for both inflation and changes in population. Another 700,000 people are expected to move to Hillsborough over the next three decades.The long-range transportation plan produced in 2014 by the Hillsborough Metropolitan Planning Organization predicts the 30-year transportation tax would raise about $8 billion in its first two decades.But it does not provide estimates for the final 10 years of the tax and used a base-year figure of about $215 million, $87 million less than now forecast.The plan assumed a growth rate of 3.58 percent based on the increase in sales tax revenues over a 23-year period that ended in 2013. That period included the Great Recession, when — from 2006 to 2009 — Florida's sales tax collections plummeted by around $8 billion.Applying the same growth rate to the state's new revenue estimates show that the tax could raise about $15.8 billion. A similar rate of growth for the 10-year school tax would yield about $1.7 billion in revenue. Contact Christopher O'Donnell at [email protected] or (813) 226-3446. Follow @codonnell_times.